diff --git a/01GAME_1373B.cpp b/01GAME_1373B.cpp
new file mode 100644
index 0000000..14886c7
--- /dev/null
+++ b/01GAME_1373B.cpp
@@ -0,0 +1,42 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+bool myc(int a,int b) {
+	return a>b;
+}
+
+int32_t main() {
+	fast();
+	test{
+		string s;
+		cin>>s;
+		int n = s.length();
+		int ones = 0;
+		int zeros = 0;
+		fr(i,0,n) if(s[i] == '0') zeros++; else ones++;
+		int e = min(zeros,ones);
+		if(e%2 == 1) cout<<"DA"<<endl;
+		else cout<<"NET"<<endl;
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/1342A.cpp b/1342A.cpp
new file mode 100644
index 0000000..2e66530
--- /dev/null
+++ b/1342A.cpp
@@ -0,0 +1,22 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+
+int32_t main(){
+	#ifndef ONLINE_JUDGE
+		freopen("input.txt","r",stdin);
+		freopen("output.txt","w",stdout);
+	#endif
+	int t;cin>>t;
+	while(t--){
+		int x,y,a,b;
+		cin>>x>>y>>a>>b;
+		int ans = 0;
+		if(b<2*a){
+			int l = abs(x-y);
+			ans = min(x,y)*b + a*l;
+		}
+		else ans = (x+y)*a;
+		cout<<ans<<endl;
+	}
+}
\ No newline at end of file
diff --git a/369NUMBERS_HB.cpp b/369NUMBERS_HB.cpp
new file mode 100644
index 0000000..5de7377
--- /dev/null
+++ b/369NUMBERS_HB.cpp
@@ -0,0 +1,67 @@
+#include<bits/stdc++.h>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+int l;
+string a, b, s;
+int dp[51][17][17][17];
+int solve(int pos, int tr, int si, int ni, int t) {
+	if (tr == l || si == l || ni == l) return 0;
+	if (pos == s.length()) return (tr == si) & (si == ni) & (tr > 0);
+	if (dp[pos][tr][si][ni] != -1 && !t) return dp[pos][tr][si][ni];
+	int e = t ? s[pos] - '0' : 9;
+	int ret = 0;
+	fr(i, 0, e + 1)	ret += solve(pos + 1, tr + (i == 3), si + (i == 6), ni + (i == 9), t & (i == e));
+	return t?ret:dp[pos][tr][si][ni] = ret % mod;
+}
+int32_t main () {
+	fast();
+	int t; cin >> t;
+	while (t--) {
+		cin >> a >> b;
+		//memset(dp, -1, sizeof dp);
+		int w3 = 0, w6 = 0, w9 = 0;
+		l = a.length()/3+1;
+		fr(i,0,a.length()) fr(j,0,l) fr(k,0,l) fr(e,0,l) dp[i][j][k][e] = -1;
+		fr(i, 0, a.length()) {
+			if (a[i] == '3') w3++;
+			else if (a[i] == '6') w6++;
+			else if (a[i] == '9') w9++;
+		}
+		s = a;
+		if (w3 > 0) w3 = (w3 == w6) & (w6 == w9);
+		int k = solve(0, 0, 0, 0, 1);
+		//memset(dp, -1, sizeof dp);
+		
+		s = b;
+		l = b.length()/3+1;
+		fr(i,0,b.length()) fr(j,0,l) fr(k,0,l) fr(e,0,l)dp[i][j][k][e] = -1;
+		int d = solve(0, 0, 0, 0, 1);
+		cout << (d - k + w3+mod)%mod << endl;
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/3n+1_Uva100.cpp b/3n+1_Uva100.cpp
new file mode 100644
index 0000000..4a06d99
--- /dev/null
+++ b/3n+1_Uva100.cpp
@@ -0,0 +1,51 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int unsigned long long
+int dp[1000001] = {0};
+
+int findVal(int k){
+	if(dp[k]) return dp[k];
+	if(k&1){
+		if(k>1000000){
+			return 2+findVal((3*k+1)>>1);
+		}
+		else{
+			int ans = 2+findVal((3*k+1)>>1);
+			dp[k]  = ans;
+			return dp[k];
+		}
+	}
+	else{
+		if(k>1000000) return 1+findVal(k/2);
+		else{
+			int ans = 1+findVal(k/2);
+			dp[k]  = ans;
+			return dp[k];
+		}
+	}
+}
+
+int32_t main(){
+	#ifndef ONLINE_JUDGE
+    freopen("input.txt" , "r",stdin);
+    freopen("output.txt","w",stdout);
+  #endif
+	dp[1] = 1;
+
+	int i,j;
+	int ans;
+	while(cin>>i&&cin>>j){
+		ans = 0;
+		if(i>j){
+			int temp = i;
+			i = j;
+			j = temp;
+		}
+		for(int h=i;h<=j;h++){
+			ans = max(ans,findVal(h));
+		}
+		
+		cout<<i<<" "<<j<<" "<<ans<<endl;
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/505_1391D.cpp b/505_1391D.cpp
new file mode 100644
index 0000000..a9bc75a
--- /dev/null
+++ b/505_1391D.cpp
@@ -0,0 +1,112 @@
+#include<bits/stdc++.h>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+    ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+    freopen("input.txt", "r", stdin);
+    freopen("output.txt", "w", stdout);
+#endif
+}
+int n,m;
+int a[1000005][3];
+int b[3][1000005];
+int32_t main () {
+    fast();
+    cin>>n>>m;
+    int k = min(n,m);
+    if(k>3){
+        int l = n*m;
+        fr(i,0,l) cin>>m;
+        cout<<"-1"<<endl;
+    }
+    else if(k==1){
+        int l = n*m;
+        fr(i,0,l) cin>>m;
+        cout<<"0";
+    }
+    else{
+        if(m>n){
+            char r;
+            fr(i,0,n) fr(j,0,m){
+                cin>>r;
+                b[i][j] = (r=='1');
+            }
+            //fr(i,0,n) {fr(j,0,m) cout<<b[i][j]; cout<<endl;}
+            fr(i,0,n) fr(j,0,m) a[j][i] = b[i][j];
+            swap(n,m);
+        }
+        else  {
+                char r;
+                fr(i,0,n) fr(j,0,m) {
+                cin>>r;
+                a[i][j] = (r=='1');            }
+        }
+      //  fr(i,0,n) {fr(j,0,m) cout<<a[i][j]; cout<<endl;}
+        if(m==2){
+            int dp[n+1][4];
+            dp[0][0] = (a[0][0]^0LL) + (a[0][1]^0LL);
+            dp[0][1] = (a[0][0]^1LL) + (a[0][1]^0LL);
+            dp[0][2] = (a[0][0]^0LL) + (a[0][1]^1LL);
+            dp[0][3] = (a[0][0]^1LL) + (a[0][1]^1LL);
+            fr(i,1,n){
+                fr(j,0,4){
+                    if(j==0) dp[i][j] = min(dp[i-1][1],dp[i-1][2]) + (a[i][0]^0LL) + (a[i][1]^0LL);
+                    else if(j==1) dp[i][j] = min(dp[i-1][0],dp[i-1][3]) + (a[i][0]^1LL) + (a[i][1]^0LL);
+                    else if(j==2) dp[i][j] = min(dp[i-1][0],dp[i-1][3]) + (a[i][0]^0LL) + (a[i][1]^1LL);
+                    else dp[i][j] = min(dp[i-1][1],dp[i-1][2]) + (a[i][0]^1LL) + (a[i][1]^1LL);
+                }
+            }
+            int ans = 1e9;
+            fr(i,0,4) ans = min(ans,dp[n-1][i]);
+            cout<<ans;
+        }
+        else{
+            int dp[n+1][8];
+            dp[0][0] = (a[0][0]^0LL) + (a[0][1]^0LL) + (a[0][2]^0LL);
+            dp[0][1] = (a[0][0]^1LL) + (a[0][1]^0LL) + (a[0][2]^0LL);
+            dp[0][2] = (a[0][0]^0LL) + (a[0][1]^1LL) + (a[0][2]^0LL);
+            dp[0][3] = (a[0][0]^1LL) + (a[0][1]^1LL) + (a[0][2]^0LL);
+            dp[0][4] = (a[0][0]^0LL) + (a[0][1]^0LL) + (a[0][2]^1LL);
+            dp[0][5] = (a[0][0]^1LL) + (a[0][1]^0LL) + (a[0][2]^1LL);
+            dp[0][6] = (a[0][0]^0LL) + (a[0][1]^1LL) + (a[0][2]^1LL);
+            dp[0][7] = (a[0][0]^1LL) + (a[0][1]^1LL) + (a[0][2]^1LL);
+            
+            fr(i,1,n){
+                fr(j,0,8){
+                    if(j==0) dp[i][j]  = min(dp[i-1][5],dp[i-1][2]) + (a[i][0]^0LL) + (a[i][1]^0LL) + (a[i][2]^0LL);
+                    else if(j==1) dp[i][j] = min(dp[i-1][4],dp[i-1][3]) + (a[i][0]^1LL) + (a[i][1]^0LL) + (a[i][2]^0LL);
+                    else if(j==2) dp[i][j] = min(dp[i-1][0],dp[i-1][7]) + (a[i][0]^0LL) + (a[i][1]^1LL) + (a[i][2]^0LL);
+                    else if(j==3) dp[i][j] = min(dp[i-1][6],dp[i-1][1]) + (a[i][0]^1LL) + (a[i][1]^1LL) + (a[i][2]^0LL);
+                    else if(j==4) dp[i][j] = min(dp[i-1][6],dp[i-1][1]) + (a[i][0]^0LL) + (a[i][1]^0LL) + (a[i][2]^1LL);
+                    else if(j==5) dp[i][j] = min(dp[i-1][0],dp[i-1][7]) + (a[i][0]^1LL) + (a[i][1]^0LL) + (a[i][2]^1LL);
+                    else if(j==6) dp[i][j] = min(dp[i-1][3],dp[i-1][4]) + (a[i][0]^0LL) + (a[i][1]^1LL) + (a[i][2]^1LL);
+                    else if(j==7) dp[i][j] = min(dp[i-1][5],dp[i-1][2]) + (a[i][0]^1LL) + (a[i][1]^1LL) + (a[i][2]^1LL);
+                    
+                }
+             //   cout<<endl;
+            }
+            int ans = 1e9;
+            fr(i,0,8) ans = min(ans,dp[n-1][i]);
+            cout<<ans;
+        }
+    }
+}
\ No newline at end of file
diff --git a/A Cookie for You_1371C.cpp b/A Cookie for You_1371C.cpp
new file mode 100644
index 0000000..a251683
--- /dev/null
+++ b/A Cookie for You_1371C.cpp	
@@ -0,0 +1,40 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+bool myc(int a,int b) {
+	return a>b;
+}
+int32_t main() {
+	fast();
+	test{
+		int a,b,n,m;
+		cin>>a>>b>>n>>m;
+		if(a+b<n+m) cout<<"No"<<endl;
+		else{
+			int d = min(a,b);
+			if(d>=m) cout<<"Yes"<<endl;
+			else cout<<"No"<<endl;
+		}
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/A Simple Task_11D.cpp b/A Simple Task_11D.cpp
new file mode 100644
index 0000000..a774378
--- /dev/null
+++ b/A Simple Task_11D.cpp	
@@ -0,0 +1,66 @@
+#include<bits/stdc++.h>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+  ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+  freopen("input.txt", "r", stdin);
+  freopen("output.txt", "w", stdout);
+#endif
+}
+int n;
+int d[25][25];
+int dp[(1<<20)][20];
+int solve(int mask,int las,int start){
+  if(__builtin_popcount(mask) == n) return d[las][start];
+  if(dp[mask][las]!=-1) return dp[mask][las];
+  int ret = 0;
+  if(__builtin_popcount(mask)>=3) ret = d[las][start];
+  fr(i,start+1,n){
+    if((!(mask&(1<<i))) && d[las][i]){
+      ret += solve((mask|(1<<i)),i,start);
+    }
+  }
+  return dp[mask][las] = ret;
+}
+
+
+int32_t main() {
+  fast();
+  memset(d,0,sizeof d);
+  
+
+  cin>>n;
+  int m;cin>>m;
+  int a,b;
+  fr(i,0,m){
+    cin>>a>>b;
+    a--;b--;
+    d[a][b] = d[b][a] = 1;
+  }
+  int ans = 0;
+  fr(s,0,n){
+    memset(dp,-1,sizeof dp);
+    ans += solve((1<<(s)),s,s)/2;
+  }
+  cout<<ans;
+  return 0;
+}
\ No newline at end of file
diff --git a/ALIENS_spoj.cpp b/ALIENS_spoj.cpp
new file mode 100644
index 0000000..912743b
--- /dev/null
+++ b/ALIENS_spoj.cpp
@@ -0,0 +1,75 @@
+#include<bits/stdc++.h>
+#include<cstdio>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+    ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+    freopen("input.txt", "r", stdin);
+    freopen("output.txt", "w", stdout);
+#endif
+}
+int32_t main () {
+        fast();
+  test{
+    int a;int b;
+    cin>>a>>b;
+    deque<int> d;
+    int ans = 0;
+    int ansS = 0;
+    int c = 0;
+    int csum = 0;
+    int k;
+    fr(i,0,a){
+        cin>>k;
+        if(k+csum<=b) {
+            d.pb(k);
+            csum+=k;
+            c++;
+            if(ans<c){
+                ans = c;
+                ansS = csum;
+            }
+            else if(ans==c){
+                if(ansS>csum)ansS = csum;
+            }
+        }
+        else{
+            csum+=k;
+            c++;
+            d.pb(k);
+            while(csum>b){
+                csum-=d.at(0);
+                c--;
+                d.pop_front();
+            }
+            if(ans<c){
+                ans = c;
+                ansS = csum;
+            }
+            else if(ans==c){
+                if(ansS>csum)ansS = csum;
+            }
+        }
+    }
+    cout<<ansS<<" "<<ans<<endl;
+  }
+}
\ No newline at end of file
diff --git a/AND OR and square sum1638D.cpp b/AND OR and square sum1638D.cpp
new file mode 100644
index 0000000..4fbf17c
--- /dev/null
+++ b/AND OR and square sum1638D.cpp	
@@ -0,0 +1,53 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif 
+}
+
+int32_t main() {
+	fast();
+	int n;
+	cin>>n;
+	int a[n+1];
+	int b[21];
+	memset(b,0,sizeof(b));
+	fr(i,0,n){
+		cin>>a[i];
+		fr(j,0,20){
+			if(a[i]&((int)(1<<j))) b[j]++;
+		}
+	}
+	fr(i,0,n){
+		int k = 0;
+		fr(j,0,20){
+			if(b[j]){
+				k += (int)(1<<j);
+				b[j]--;
+			}
+		}
+		a[i] = k;
+	}
+	int ans = 0;
+	fr(i,0,n) ans+= a[i]*a[i];
+	cout<<ans;
+
+	return 0;
+}
\ No newline at end of file
diff --git a/A_and_B_Team_Training_519C.cpp b/A_and_B_Team_Training_519C.cpp
new file mode 100644
index 0000000..18bab7d
--- /dev/null
+++ b/A_and_B_Team_Training_519C.cpp
@@ -0,0 +1,10 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+
+int32_t main(){
+	int n,m;
+	cin>>n>>m;
+	cout<<min(n,min(m,(m+n)/3));
+	return 0;
+}
\ No newline at end of file
diff --git a/Acacius and String_1379A.cpp b/Acacius and String_1379A.cpp
new file mode 100644
index 0000000..b997d47
--- /dev/null
+++ b/Acacius and String_1379A.cpp	
@@ -0,0 +1,98 @@
+#include<bits/stdc++.h>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+
+int32_t main() {
+	fast();
+	test{
+		int n;
+		cin >> n;
+		string s;
+		cin >> s;
+		string a = "abacaba";
+		int st, e;
+		int ans = 0;
+		fr(i, 0, n - 6) {
+			fr(j, i, i + 7) {
+				if (s[j] != a[j - i])break;
+				else if (j == i+6) ans++;
+			}
+		}
+		if (ans > 1) cout << "No" << endl;
+		else if (ans == 1) {
+			cout << "Yes" << endl;
+			fr(i, 0, n) {
+				if (s[i] != '?')cout << s[i];
+				else cout << "x";
+			}
+			cout<<endl;
+		}
+		else{
+			ans = 0;
+			//cout<<"end";
+			fr(i, 0, n - 6) {
+				vi v;
+				int as = 0;
+				fr(j, i, i + 7) {
+					if (s[j] != a[j - i] && s[j] != '?')break;
+					else {
+						if (j == i + 6) {
+							//cout<<"end";
+							fr(k, i, i + 7) if (s[k] == '?') {s[k] = a[k - i]; v.pb(k);}
+							as = 1;
+						}
+					}
+				}
+				if (as) {
+					int alt = 0;
+					fr(i, 0, n - 6) {
+						fr(j, i, i + 7) {
+							if (s[j] != a[j - i])break;
+							else if (j == i+6) alt++;
+						}
+					}
+					if (alt > 1) {
+						for (auto x : v) s[x] = '?';
+					}
+					else if (alt == 1) ans = 1;
+				}
+				if (ans) break;
+			}
+			if (ans) {
+				cout << "Yes" << endl;
+				fr(i, 0, n) {
+					if (s[i] != '?')cout << s[i];
+					else cout << "x";
+				}
+				cout<<endl;
+			}
+			else cout<<"No"<<endl;
+		}
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/AccurateLee_1369B.cpp b/AccurateLee_1369B.cpp
new file mode 100644
index 0000000..78b9174
--- /dev/null
+++ b/AccurateLee_1369B.cpp
@@ -0,0 +1,66 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int unsigned long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+bool myc(pair<string,int> a, pair<string,int> b) {
+	if(a.fi == b.fi) return a.se<b.se;
+	return a.fi<b.fi;
+}
+
+int32_t main() {
+	fast();
+	test{
+		int n;
+		string s;
+		cin>>n>>s;
+		int k = 0;
+		stack<char> st;
+		int r = n-1;
+		while(s[r]=='1' && r>=0){
+			st.pu('1');
+			r--;
+		}
+		r = 0;
+		while(s[r]=='0' && r<=n-1){
+			st.pu('0');
+			r++;
+		}
+		fr(i,r,n){
+			if(s[i] == '0'){
+				k=1;
+				break;
+			}
+		}
+		while(!st.empty()){
+			if(st.top()=='1') break;
+			cout<<st.top();
+			st.pop();
+		}
+		if(k == 1) cout<<"0";
+		while(!st.empty()){
+			cout<<st.top();
+			st.pop();
+		}
+		cout<<endl;
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/Add Arithmetic Progression On Segment_CF_Pilot.cpp b/Add Arithmetic Progression On Segment_CF_Pilot.cpp
new file mode 100644
index 0000000..9ad0e17
--- /dev/null
+++ b/Add Arithmetic Progression On Segment_CF_Pilot.cpp	
@@ -0,0 +1,109 @@
+#include<bits/stdc++.h>
+//#include<ext/pb_ds/assoc_container.hpp>
+//#include<ext/pb_ds/tree_policy.hpp>
+//using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+/*
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;*/
+void fast() {
+  ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+  freopen("input.txt", "r", stdin);
+  freopen("output.txt", "w", stdout);
+#endif
+}
+
+int tree[800004];
+int lazy[800004][3];
+
+void update(int s,int e,int qs,int qe,int i,int a,int d){
+  if(lazy[i][0]){
+    tree[i]+=((e-s+1)*( 2*lazy[i][1]  + lazy[i][2]*(e-s)))/2;
+    if(s!=e){
+      lazy[2*i][0] = lazy[2*i+1][0] = 1;
+      lazy[2*i][1] += lazy[i][1];
+      lazy[2*i][2] += lazy[i][2];
+      lazy[2*i+1][1] += lazy[i][1] + ((s+e)/2 - s +1)*lazy[i][2];
+      lazy[2*i+1][2] += lazy[i][2];
+    }
+    lazy[i][0] = lazy[i][1] = lazy[i][2] = 0;
+  }
+  if(qs<=s && qe>=e){
+    tree[i]+=((e-s+1)*( 2*a  + d*(e-s)))/2;
+    if(s!=e){
+      lazy[2*i][0] = lazy[2*i+1][0] = 1;
+      lazy[2*i][1] += a;
+      lazy[2*i][2] += d;
+      lazy[2*i+1][1] += a+((s+e)/2-s +1)*d;
+      lazy[2*i+1][2] += d;
+    }
+    return;
+  }
+  if(s>qe || e<qs) return;
+  int r = (s+e)/2-max(s,qs)+1;
+  if(r>0){
+    update(s,(s+e)/2,qs,qe,2*i,a,d);
+    update((s+e)/2+1,e,qs,qe,2*i+1,a+(r)*d,d);
+  }
+  else{
+    update((s+e)/2+1,e,qs,qe,2*i+1,a,d);
+  }
+  tree[i] = tree[2*i]+tree[2*i+1];
+}
+int query(int s,int e,int pi,int i){
+  if(lazy[i][0]){
+    tree[i]+=((e-s+1)*( 2*lazy[i][1]  + lazy[i][2]*(e-s)))/2;
+    if(s!=e){
+      lazy[2*i][0] = lazy[2*i+1][0] = 1;
+      lazy[2*i][1] += lazy[i][1];
+      lazy[2*i][2] += lazy[i][2];
+      lazy[2*i+1][1] += lazy[i][1] + ((s+e)/2 - s +1)*lazy[i][2];
+      lazy[2*i+1][2] += lazy[i][2];
+    }
+    lazy[i][0] = lazy[i][1] = lazy[i][2] = 0;
+  }
+  if(s==e && pi==s) return tree[i];
+  else if(e<pi || s>pi) return 10000000000000000;
+  int l = query(s,(s+e)/2,pi,2*i);
+  int r = query((s+e)/2+1,e,pi,2*i+1);
+  return min(l,r);
+}
+
+int32_t main() {
+  fast();
+  memset(tree,0,sizeof tree);
+  memset(lazy,0,sizeof lazy);
+  int n,m;
+  cin>>n>>m;
+  int a,b,c,d;
+  int r;
+  fr(i,0,m){
+    cin>>a;
+    if(a==1){
+      cin>>b>>c>>d>>r;
+      update(0,n-1,b-1,c-1,1,d,r);
+      //cout<<d<<" "<<r<<endl;
+      //cout<<query(0,n-1,b,1)<<endl;
+    }
+    else{
+      cin>>b;
+      cout<<query(0,n-1,b-1,1)<<endl;
+    }
+  }
+  return 0;
+}
\ No newline at end of file
diff --git a/Addition and Minimum_CF_Pilot.cpp b/Addition and Minimum_CF_Pilot.cpp
new file mode 100644
index 0000000..739d6d8
--- /dev/null
+++ b/Addition and Minimum_CF_Pilot.cpp	
@@ -0,0 +1,92 @@
+#include<bits/stdc++.h>
+//#include<ext/pb_ds/assoc_container.hpp>
+//#include<ext/pb_ds/tree_policy.hpp>
+//using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+/*
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;*/
+void fast() {
+  ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+  freopen("input.txt", "r", stdin);
+  freopen("output.txt", "w", stdout);
+#endif
+}
+
+int tree[400004];
+int lazy[400004];
+
+void update(int s,int e,int qs,int qe,int i,int up){
+  if(lazy[i]){
+    tree[i]+=lazy[i];
+    if(s!=e){
+      lazy[2*i] += lazy[i];
+      lazy[2*i+1] += lazy[i];
+    }
+    lazy[i] = 0;
+  }
+  if(qs<=s && qe>=e){
+    tree[i]+=up;
+    if(s!=e){
+      lazy[2*i] += up;
+      lazy[2*i+1] += up;
+    }
+    return;
+  }
+  if(s>qe || e<qs) return;
+  update(s,(s+e)/2,qs,qe,2*i,up);
+  update((s+e)/2+1,e,qs,qe,2*i+1,up);
+  tree[i] = min(tree[2*i],tree[2*i+1]);
+}
+int query(int s,int e,int qs,int qe,int i){
+  if(lazy[i]){
+    tree[i]+=lazy[i];
+    if(s!=e){
+      lazy[2*i] += lazy[i];
+      lazy[2*i+1] += lazy[i];
+    }
+    lazy[i] = 0;
+  }
+  if(s>=qs && e<=qe) return tree[i];
+  else if(s>qe || e<qs) return 1000000000000000;
+  int l = query(s,(s+e)/2,qs,qe,2*i);
+  int r = query((s+e)/2+1,e,qs,qe,2*i+1);
+  return min(l,r);
+}
+
+int32_t main() {
+  fast();
+  memset(tree,0,sizeof tree);
+  memset(lazy,0,sizeof lazy);
+  int n,m;
+  cin>>n>>m;
+  int a,b,c,d;
+  fr(i,0,m){
+    cin>>a;
+    if(a==1){
+      cin>>b>>c>>d;
+      update(0,n-1,b,c-1,1,d);
+      //cout<<query(0,n-1,b,1)<<endl;
+    }
+    else{
+      cin>>b>>c;
+      cout<<query(0,n-1,b,c-1,1)<<endl;
+    }
+  }
+  return 0;
+}
\ No newline at end of file
diff --git a/Addition and Sum_CF_Pilot.cpp b/Addition and Sum_CF_Pilot.cpp
new file mode 100644
index 0000000..74f72a1
--- /dev/null
+++ b/Addition and Sum_CF_Pilot.cpp	
@@ -0,0 +1,92 @@
+#include<bits/stdc++.h>
+//#include<ext/pb_ds/assoc_container.hpp>
+//#include<ext/pb_ds/tree_policy.hpp>
+//using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+/*
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;*/
+void fast() {
+  ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+  freopen("input.txt", "r", stdin);
+  freopen("output.txt", "w", stdout);
+#endif
+}
+
+int tree[400004];
+int lazy[400004];
+
+void update(int s,int e,int qs,int qe,int i,int up){
+  if(lazy[i]){
+    tree[i]+=(e-s+1)*lazy[i];
+    if(s!=e){
+      lazy[2*i] += lazy[i];
+      lazy[2*i+1] += lazy[i];
+    }
+    lazy[i] = 0;
+  }
+  if(qs<=s && qe>=e){
+    tree[i]+=(e-s+1)*up;
+    if(s!=e){
+      lazy[2*i] += up;
+      lazy[2*i+1] += up;
+    }
+    return;
+  }
+  if(s>qe || e<qs) return;
+  update(s,(s+e)/2,qs,qe,2*i,up);
+  update((s+e)/2+1,e,qs,qe,2*i+1,up);
+  tree[i] = tree[2*i]+tree[2*i+1];
+}
+int query(int s,int e,int qs,int qe,int i){
+  if(lazy[i]){
+    tree[i]+=(e-s+1)*lazy[i];
+    if(s!=e){
+      lazy[2*i] += lazy[i];
+      lazy[2*i+1] += lazy[i];
+    }
+    lazy[i] = 0;
+  }
+  if(s>=qs && e<=qe) return tree[i];
+  else if(s>qe || e<qs) return 0;
+  int l = query(s,(s+e)/2,qs,qe,2*i);
+  int r = query((s+e)/2+1,e,qs,qe,2*i+1);
+  return l+r;
+}
+
+int32_t main() {
+  fast();
+  memset(tree,0,sizeof tree);
+  memset(lazy,0,sizeof lazy);
+  int n,m;
+  cin>>n>>m;
+  int a,b,c,d;
+  fr(i,0,m){
+    cin>>a;
+    if(a==1){
+      cin>>b>>c>>d;
+      update(0,n-1,b,c-1,1,d);
+      //cout<<query(0,n-1,b,1)<<endl;
+    }
+    else{
+      cin>>b>>c;
+      cout<<query(0,n-1,b,c-1,1)<<endl;
+    }
+  }
+  return 0;
+}
\ No newline at end of file
diff --git a/Addition to Segment_CF_Pilot.cpp b/Addition to Segment_CF_Pilot.cpp
new file mode 100644
index 0000000..1e00f71
--- /dev/null
+++ b/Addition to Segment_CF_Pilot.cpp	
@@ -0,0 +1,91 @@
+#include<bits/stdc++.h>
+//#include<ext/pb_ds/assoc_container.hpp>
+//#include<ext/pb_ds/tree_policy.hpp>
+//using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+/*
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;*/
+void fast() {
+  ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+  freopen("input.txt", "r", stdin);
+  freopen("output.txt", "w", stdout);
+#endif
+}
+
+int tree[400004];
+int lazy[400004];
+
+void update(int s,int e,int qs,int qe,int i,int up){
+  if(lazy[i]){
+    tree[i]+=lazy[i];
+    if(s!=e){
+      lazy[2*i] += lazy[i];
+      lazy[2*i+1] += lazy[i];
+    }
+    lazy[i] = 0;
+  }
+  if(qs<=s && qe>=e){
+    tree[i]+=up;
+    if(s!=e){
+      lazy[2*i] += up;
+      lazy[2*i+1] += up;
+    }
+    return;
+  }
+  if(s>qe || e<qs) return;
+  update(s,(s+e)/2,qs,qe,2*i,up);
+  update((s+e)/2+1,e,qs,qe,2*i+1,up);
+}
+int query(int s,int e,int pi,int i){
+  if(lazy[i]){
+    tree[i]+=lazy[i];
+    if(s!=e){
+      lazy[2*i] += lazy[i];
+      lazy[2*i+1] += lazy[i];
+    }
+    lazy[i] = 0;
+  }
+  if(s==e && s==pi) return tree[i];
+  else if(s>pi || e<pi) return 1000000000000000;
+  int l = query(s,(s+e)/2,pi,2*i);
+  int r = query((s+e)/2+1,e,pi,2*i+1);
+  return min(l,r);
+}
+
+int32_t main() {
+  fast();
+  memset(tree,0,sizeof tree);
+  memset(lazy,0,sizeof lazy);
+  int n,m;
+  cin>>n>>m;
+  int a,b,c,d;
+  fr(i,0,m){
+    cin>>a;
+    if(a==1){
+      cin>>b>>c>>d;
+      update(0,n-1,b,c-1,1,d);
+      //cout<<query(0,n-1,b,1)<<endl;
+    }
+    else{
+      cin>>d;
+      cout<<query(0,n-1,d,1)<<endl;
+    }
+  }
+  return 0;
+}
\ No newline at end of file
diff --git a/Ahahahahahahahaha_1407A.cpp b/Ahahahahahahahaha_1407A.cpp
new file mode 100644
index 0000000..d1072d4
--- /dev/null
+++ b/Ahahahahahahahaha_1407A.cpp
@@ -0,0 +1,64 @@
+#include<bits/stdc++.h>
+#include<cstdio>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+    ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+    freopen("input.txt", "r", stdin);
+    freopen("output.txt", "w", stdout);
+#endif
+}
+
+
+
+int32_t main() {
+    fast();
+    test{
+        int n;
+        cin>>n;
+        int a[n+1];
+        fr(i,0,n) cin>>a[i];   
+        int cnt1 = 0;
+        int cnt0 = 0;
+        fr(i,0,n){
+            cnt1 += (a[i]==1);
+            cnt0 += (a[i]==0);
+        }
+        if(cnt0<n/2){
+            if((n-cnt0)%2==0){
+                cout<<n-cnt0<<endl;
+                fr(i,0,(n-cnt0)) cout<<"1"<<" ";
+                cout<<endl;
+            }
+            else{
+                cout<<n-cnt0-1<<endl;
+                fr(i,0,n-cnt0-1) cout<<"1 ";
+                cout<<endl;
+            }
+        }
+        else{
+            cout<<cnt0<<endl;
+            fr(i,0,cnt0) cout<<'0'<<" ";
+            cout<<endl;
+        }
+    }
+}
diff --git a/Airthmetic_progression_382C.cpp b/Airthmetic_progression_382C.cpp
new file mode 100644
index 0000000..edc29ee
--- /dev/null
+++ b/Airthmetic_progression_382C.cpp
@@ -0,0 +1,102 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+
+int32_t main() {
+	fast();
+	int n; cin >> n;
+	int a[n + 1];
+	fr(i, 0, n) cin >> a[i];
+	sort(a, a + n);
+	if (n == 1) cout << "-1";
+	else if (n == 2) {
+		if (a[1] - a[0] == 0) {
+			cout << "1" << endl << a[0];
+			return 0;
+		}
+		vi ans;
+		if ((a[0] + a[1]) % 2 == 0) {
+			ans.pb((a[0] + a[1]) / 2);
+		}
+		ans.pb(a[0] - (a[1] - a[0]));
+		ans.pb(a[1] + (a[1] - a[0]));
+		cout << ans.size() << endl;
+		sort(ans.begin(), ans.end());
+		for (auto i : ans) cout << i << " ";
+	}
+	else {
+		int d = 0;
+		fr(i, 1, n) {
+			if (a[i] - a[i - 1] == 0) {
+				d++;
+			}
+		}
+		if (d == n - 1) {
+			cout << "1" << endl << a[0];
+		}
+		else if (d > 0) cout << '0';
+		else {
+			set<int> k;
+			int l = 0;
+			fr(i, 1, n) {
+				k.insert(a[i] - a[i - 1]);
+				if (k.size() > 2) {
+					l = 1;
+					break;
+				}
+			}
+			if (l == 1) cout << "0";
+			else if (k.size() == 1) {
+				vi ans;
+				ans.pb(a[0] - (a[1] - a[0]));
+				ans.pb(a[n - 1] + (a[1] - a[0]));
+				cout << ans.size() << endl;
+				sort(ans.begin(), ans.end());
+				for (auto i : ans) cout << i << " ";
+			}
+			else {
+				std::set<int>::iterator it = k.begin();
+				vi d;
+				while (it != k.end())
+				{
+					d.pb((*it));
+					it++;
+				}
+				if (d[1] != 2 * d[0]) cout << "0";
+				else {
+					vi ind;
+					fr(i, 1, n) {
+						if (a[i] - a[i - 1] == d[1]) {
+							ind.pb(i);
+						}
+					}
+					if (ind.size() > 1) cout << "0";
+					else {
+						cout << "1" << endl;
+						cout << a[ind[0]] - d[0];
+					}
+				}
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/Alice_Bobs&Chocolates_6C.cpp b/Alice_Bobs&Chocolates_6C.cpp
new file mode 100644
index 0000000..cd2284d
--- /dev/null
+++ b/Alice_Bobs&Chocolates_6C.cpp
@@ -0,0 +1,27 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+
+int32_t main(){
+	#ifndef ONLINE_JUDGE
+		freopen("input.txt","r",stdin);
+		freopen("output.txt","w",stdout);
+	#endif
+	int n;
+	cin>>n;
+	int a[n+1];
+	for (int i = 0; i < n; ++i) cin>>a[i];
+
+	int aa[n+1]; aa[0] = 0;
+	int ba[n+1]; ba[n-1]= 0;
+	for(int i=1;i<n;i++){
+		aa[i] = aa[i-1]+a[i-1];
+		ba[n-i-1] = ba[n-i] + a[n-i];
+	}
+	int i = 0;
+	while(aa[i]<=ba[i] && i<n) i++;
+	cout<<i<<" "<<n-i;
+	
+
+	return 0;
+}
\ No newline at end of file
diff --git a/Alice_and_Bob_346A.cpp b/Alice_and_Bob_346A.cpp
new file mode 100644
index 0000000..2d7404f
--- /dev/null
+++ b/Alice_and_Bob_346A.cpp
@@ -0,0 +1,33 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+
+int32_t main(){
+	#ifndef ONLINE_JUDGE
+		freopen("input.txt","r",stdin);
+		freopen("output.txt","w",stdout);
+	#endif
+	int n;
+	cin>>n;
+	vector<int> a;
+	int l;
+	unordered_map<int,int> m;
+	for(int i=0;i<n;i++){
+		cin>>l;
+		a.push_back(l);
+		m[l] = 1;
+	}
+	int d = 0;
+	for(int i=0;i<n;i++){
+		for(int j=i+1;j<n;j++){
+			if(m.count(abs(a[i]-a[j]))==0){
+				d++;
+				m[abs(a[i]-a[j])] = 1;
+				a.push_back(abs(a[i]-a[j]));
+				n++;
+			}
+		}
+	}
+	if(d%2==1) cout<<"Alice";
+	else cout<<"Bob";
+}
\ No newline at end of file
diff --git a/Alyona and Strings_682D.cpp b/Alyona and Strings_682D.cpp
new file mode 100644
index 0000000..2bca369
--- /dev/null
+++ b/Alyona and Strings_682D.cpp	
@@ -0,0 +1,65 @@
+#include<bits/stdc++.h>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<pii, null_type, greater<pii>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+string a, b;
+int dp[1002][1002][11][2];
+int k; int n; int m;
+int solve(int x, int y, int rem, int c) {
+	if (x == n || y == m) {
+		if (rem == 0) return 0;
+		else return -1000000000;
+	}
+	if (rem == 0) return 0;
+	if (dp[x][y][rem][c] != -1) return dp[x][y][rem][c];
+	int ans;
+	if (c == 1) {
+		ans = solve(x + 1, y, rem - 1, 0);
+		ans = max(ans, solve(x, y + 1, rem - 1, 0));
+		if (a[x] == b[y]) {
+			ans = max(ans, 1 + solve(x + 1, y + 1, rem, 1));
+			ans = max(ans, 1 + solve(x + 1, y + 1, rem - 1, 0));
+		}
+	}
+	else {
+		ans = solve(x + 1, y, rem, 0);
+		ans = max(ans, solve(x, y + 1, rem, 0));
+		if (a[x] == b[y]) {
+			ans = max(ans, 1 + solve(x + 1, y + 1, rem, 1));
+			ans = max(ans, 1 + solve(x + 1, y + 1, rem - 1, 0));
+		}
+	}
+	return dp[x][y][rem][c] = ans;
+}
+int32_t main() {
+	fast();
+	cin >> n >> m >> k;
+	cin >> a >> b;
+	memset(dp, -1, sizeof(dp));
+	cout << solve(0, 0, k, 0);
+	return 0;
+}
\ No newline at end of file
diff --git a/Alyona and the Tree_682C.cpp b/Alyona and the Tree_682C.cpp
new file mode 100644
index 0000000..fc66325
--- /dev/null
+++ b/Alyona and the Tree_682C.cpp	
@@ -0,0 +1,70 @@
+#include<bits/stdc++.h>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+#define N 100005
+int a[N];
+vector<vpi> g(N);
+int n;
+int ans = 0;
+int sz[N];
+int nc(int i,int p){
+    int dz = 1;
+   // cout<<i<<endl;
+    for(auto x:g[i]){
+        if(x.first!=p){
+            dz+= nc(x.first,i);
+        }
+    }
+    sz[i] = dz;
+    return dz;
+}
+void dfs(int i,int p,int xi){
+    if(a[i]<xi)return;
+    ans++;
+    cout<<i<<endl;
+    for(auto x:g[i]){
+        if(x.first!=p){
+            dfs(x.first,i,max(0LL,xi+x.second) );
+        }
+    }
+}
+
+int32_t main(){
+    fast();
+    cin>>n;
+    fr(i,1,n+1) cin>>a[i];
+    int x,y;
+    fr(i,2,n+1){
+        cin>>x>>y;
+        g[i].pb(mp(x,y));
+        g[x].pb(mp(i,y));
+    }
+    nc(1,0); //cout<<sz[1]<<endl;
+    dfs(1,0,0);
+    cout<<n-ans;
+}
\ No newline at end of file
diff --git a/a-Good String_1385D.cpp b/a-Good String_1385D.cpp
new file mode 100644
index 0000000..6e8c3d4
--- /dev/null
+++ b/a-Good String_1385D.cpp	
@@ -0,0 +1,72 @@
+#include<bits/stdc++.h>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+using namespace __gnu_pbds;
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define fi first
+#define se second
+#define mod 1000000007
+typedef tree<int, null_type, less<int>, rb_tree_tag,
+        tree_order_statistics_node_update> seti;
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+int n;
+int bit[150000][27];
+string s;
+//void buildTree()
+
+
+void update(int i,char a){
+	while(i<=n){
+		bit[i][a-'a'] +=1;
+		i += (i)&(-i);
+	}
+}
+int query(int i,char ch){
+	int sum = 0;
+	while(i>0){
+		sum += bit[i][ch-'a'];
+		i-= i&(-i);
+	}
+	return sum;
+}
+
+int minG(int st,int e,char ch){
+	int l = 0;
+	if(st == e) return s[st-1] != ch;
+	l += ((st+e)/2 +1-st) -(query((st+e)/2,ch) - query(st-1,ch));
+	l += minG((st+e)/2+1,e,ch+1);
+	int k = 0;
+	k += (e - ((st+e)/2 +1) +1) - (query(e,ch) - query((st+e)/2,ch));
+	k += minG(st,(st+e)/2,ch+1);
+	return min(k,l);
+}
+int32_t main() {
+	fast();
+	test{
+
+		cin>>n;
+		fr(i,0,n+1)fr(j,0,26) bit[i][j] = 0;
+		//string s;
+		cin>>s;
+		fr(i,0,n)	update(i+1,s[i]);
+		cout<<minG(1,n,'a')<<endl;
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/almost_Airthmetic_Progression_255C.cpp b/almost_Airthmetic_Progression_255C.cpp
new file mode 100644
index 0000000..c7be2c3
--- /dev/null
+++ b/almost_Airthmetic_Progression_255C.cpp
@@ -0,0 +1,48 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+#define fr(i,a,b) for(int i=a;i<b;i++)
+#define frn(i,a,b) for(int i=a;i>=b;i--)
+#define vi vector<int>
+#define pii pair<int,int>
+#define vpi vector<pair<int,int>>
+#define vvi vector<vector<int>>
+#define test int t;cin>>t; while(t--)
+#define mp make_pair
+#define pb push_back
+#define pu push
+#define mod 1000000007
+void fast() {
+	ios_base::sync_with_stdio(false); cin.tie(NULL);
+#ifndef ONLINE_JUDGE
+	freopen("input.txt", "r", stdin);
+	freopen("output.txt", "w", stdout);
+#endif
+}
+int dp[4005][4005];
+int32_t main() {
+	fast();
+	memset(dp, 0, sizeof dp);
+	int n;
+	cin >> n;
+	int a[n + 1];
+	unordered_map<int, int> m;
+	fr(i, 0, n) cin >> a[i];
+	int ans = 1;
+	fr(i, 0, n) {
+		fr(j, 0, i) {
+			if (m.count(a[i])) {
+				dp[i][j] = 1 + dp[j][m[a[i]]];
+			}
+			else dp[i][j] = 2;
+			m[a[j]] = j;
+			//cout<<dp[i][j]<<" ";
+			ans = max(ans,dp[i][j]);
+		}
+	//	cout<<endl;
+
+		m.clear();
+	}
+
+	cout << ans;
+}
\ No newline at end of file