dls.cpp

/*bismillahir~rahmanir~rahim*/
#include <bits/stdc++.h>
#pragma GCC target("popcnt")
using namespace std;

#define ll   long long int
#define yes    printf("YES\n")
#define no     printf("NO\n")


bool DLS (vector<vector<int>>& g,ll start, ll goal , ll limit ){
    
    //if we reached the goal
    if(start == goal){
        return true;
    }

    //if we crossed limit
    if(limit == 0){
        return false;
    }

    //traversing child nodes 
    for(auto i : g[start]){
        if(DLS(g,i,goal,limit-1)){
            return true;
        }
    }    
    return false;
}


int main(){
    
    ios_base::sync_with_stdio(false);
    cin.tie(NULL), cout.tie(NULL);
    
    // taking input the numbers of nodes and edges
    cout<<"Enter the number of nodes and edges:\n";
    ll n, m;
    cin >> n >> m;

    // adjacency list   
    vector<vector<int>> graph(n+1);

    // taking input the edges
    cout<<"Enter the edges:\n";
    for(int i=0;i<m;i++){
        ll u, v;
        cin >> u >> v;
        graph[u].push_back(v);  
        graph[u].push_back(v);  
    }

    // taking input the start and goal node
    cout<<"Enter the start and goal node and limit:\n";
    ll goal , limit , start;
    cin >> start >> goal >> limit;

    if(DLS(graph,start,goal,limit)) cout << "Yes, it is possible to reach the goal \n";
    else cout << "No, it isn't possible to reach the goal \n";
}

/*
input 1 : 

9 8
1 2
1 3
2 4
2 5
5 8
3 6
6 7
7 9
1 3 2

output 1 : Yes, it is possible to reach the goal

input 2 : 

9 8
1 2
1 3
2 4
2 5
5 8
3 6
6 7
7 9
1 9 2

output 1 : No, it isn't possible to reach the goal

*/