From 9e285869eb141c1e69093c1a8d3bf637e49bbc9e Mon Sep 17 00:00:00 2001
From: shubh agrawal <shubh.coding@gmail.com>
Date: Sat, 3 Oct 2020 11:28:38 +0530
Subject: [PATCH] adding some more graph algorithms

---
 Library/Graph/PRIMS.CPP         | 68 ++++++++++++++++++++++++++++++++
 Library/Graph/floydwarshall.cpp | 69 +++++++++++++++++++++++++++++++++
 2 files changed, 137 insertions(+)
 create mode 100644 Library/Graph/PRIMS.CPP
 create mode 100644 Library/Graph/floydwarshall.cpp

diff --git a/Library/Graph/PRIMS.CPP b/Library/Graph/PRIMS.CPP
new file mode 100644
index 0000000..1d6cf5d
--- /dev/null
+++ b/Library/Graph/PRIMS.CPP
@@ -0,0 +1,68 @@
+#include<iostream>
+#define I 32767
+using namespace std;
+int main()
+{int cost[8][8]={{I,I,I,I,I,I,I,I},
+		{I,I,25,I,I,I,5,I},
+		{I,25,I,12,I,I,I,10},
+		{I,I,12,I,8,I,I,I},
+		{I,I,I,8,I,16,I,14},
+		{I,I,I,I,16,I,20,18},
+		{I,5,I,I,I,20,I,I},
+		{I,I,10,I,14,18,I,I}};
+int near[8]={I,I,I,I,I,I,I,I};
+int t[2][6];
+int i,j,u,v,k,n=7,min=I;
+for(i=1;i<=n;i++)
+{
+for(j=i;j<=n;j++)
+{if(cost[i][j]<min)
+{min=cost[i][j];
+u=i;
+v=j;
+}
+}
+}
+t[0][0]=u;
+t[1][0]=v;
+near[u]=0;
+near[v]=0;
+for(j=1;j<=n;j++)
+{if(near[j]!=0)
+{
+if(cost[j][u]<cost[j][v])
+{near[j]=u;
+}
+else
+{near[j]=v;
+}
+}
+}
+for(i=1;i<n-1;i++)//this is for t array that means for nodes
+{
+	min=I;
+	for(j=1;j<=n;j++)
+	{
+		if(near[j]!=0 && cost[j][near[j]]<min)
+		{min=cost[j][near[j]];
+		k=j;
+		
+		}
+	}
+	t[0][i]=k;
+	t[1][i]=near[k];
+	near[k]=0;
+	for(j=1;j<=n;j++)
+	{
+		if(near[j]!=0 && cost[j][k]<cost[j][near[j]])
+		{
+			near[j]=k;
+		}
+	}
+}
+for(i=0;i<n-1;i++)
+{
+	cout<<"("<<t[0][i]<<","<<t[1][i]<<")"<<endl;
+}
+return 0;
+}
diff --git a/Library/Graph/floydwarshall.cpp b/Library/Graph/floydwarshall.cpp
new file mode 100644
index 0000000..4d29081
--- /dev/null
+++ b/Library/Graph/floydwarshall.cpp
@@ -0,0 +1,69 @@
+#include<iostream>
+using namespace std;
+#define INF 1e7
+void floydwarshall(int m[][100],int n)
+{
+    int dist[n][n];
+    
+    for(int i=0;i<n;i++)
+        {
+            for(int j=0;j<n;j++)
+            {
+                dist[i][j]=m[i][j];
+            }
+        }
+    for(int k=0;k<n;k++)
+    {
+        for(int i=0;i<n;i++)
+        {
+            for(int j=0;j<n;j++)
+            {
+                if(dist[i][k]+dist[k][j]<dist[i][j])
+                dist[i][j]=dist[i][k]+dist[k][j];
+            }
+        }
+    }
+    for(int i=0;i<n;i++)
+        {
+        for(int j=0;j<n;j++)
+        {
+            if(dist[i][j]==INF)
+            cout<<"INF"<<" ";
+            else
+            cout<<dist[i][j]<<" ";
+        }
+        cout<<endl;
+        }
+}
+int main()
+ {
+	int t;
+	cin>>t;
+	while(t--)
+	{
+	    int n;
+	    cin>>n;
+	    int m[100][100];
+	    for(int i=0;i<n;i++)
+	    {
+	        for(int j=0;j<n;j++)
+	        {
+	            cin>>m[i][j];
+	        }
+	    }
+	    floydwarshall(m,n);
+	    
+	    /*for(int i=0;i<n;i++)
+	    {
+	        for(int j=0;j<n;j++)
+	        {
+	            if(m[i][j]==INF)
+	            cout<<"INF"<<" ";
+	            else
+	            cout<<m[i][j]<<" ";
+	        }
+	        cout<<endl;
+	    }*/
+	}
+	return 0;
+}
\ No newline at end of file