Bellman Ford

///:-)
#include <bits/stdc++.h>
#define pb push_back
#define ll long long int
#define inf 2000000000
#define infLL 9000000000000000000
#define infULL 18446744073709551615
#define Aktaruzzaman using
#define pi (2.0*acos(0.0))
#define Pramanik namespace std;
#define vsort(v)   sort(v.begin(),v.end())
#define ull unsigned long long int
#define mem(a, b) memset(a, b, sizeof a)
#define cf 100009
#define MOD 1000000007
#define pii pair<int, int>

//int dx[]={0,1,0,-1};
//int dy[]={1,0,-1,0};
//int dx[]={1,1,0,-1,-1,-1,0,1};
//int dy[]={0,1,1,1,0,-1,-1,-1};

template <class T> inline T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template< class T > inline T lcm(T a,T b) {a=abs(a);b=abs(b); return (a/gcd(a,b))*b;}
template <class T> inline T is_prime(T a){if(a<2|a==4)return false;if(a==2||a==3||a==5)return true; T g=(T)sqrt(a)+1; for(T i=2; i<=g; i++){if(a%i==0)return false;}return false;}
template <class T> inline T bigmod(T n,T p,T m){if(p==0)return 1; if(p%2)return ((n%m)*bigmod(n,p-1,m))%m; else {T c=bigmod(n,p/2,m);return ((c%m)*(c%m))%m;}}

Aktaruzzaman Pramanik



int main()
{
    //freopen("input.txt","r",stdin)
    //freopen("output.txt","w",stdout)

    int dis[100];
    int cost[101][101];
    vector<int>a[100];
    int n, i, j, k, x, y, m, c, src;

    scanf("%d%d", &n, &m);

    for(i=1; i<=m; i++){
        scanf("%d%d%d", &x, &y, &c);
        a[x].pb(y);
        a[y].pb(x);
        cost[x][y]=c;
        cost[y][x]=c;
    }

    for(i=1; i<=n; i++)dis[i]=inf;

    scanf("%d", &src);
    dis[src]=0;

    for(i=1; i<n; i++){

        for(j=1; j<=m; j++){
            for(k=0; k<a[j].size(); k++){
                y = a[j][k];
                if(dis[y]>cost[j][y]+dis[j]){
                    dis[y]=cost[j][y]+dis[j];
                }
            }
        }

    }

    int flg=0;

    for(j=1; j<=m; j++){
            for(k=0; k<a[j].size(); k++){
                y = a[j][k];
                if(dis[y]>cost[j][y]+dis[j]){
                        flg=1;
                    cout<<"Neg Cycle\n"<<endl;
                    break;
                }
            }
            if(flg)break;
        }
    if(!flg)printf("NO NEGATIVE CYCLE\n");
    for(i=1; i<=n; i++)a[i].clear();

    return main();
}