bellman_ford 判负圈问题 图

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <queue>
#include <stack>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <set>
using namespace std;
const int INF = 10000000;

int n,v,d[10000];
struct node {
	int f,e;
	int w;

};
node a[10000];

void bllman_ford(int s){
	for(int i = 1;i <= n;i++){
		d[i] = INF;
	}
	d[s] = 0;
	for(int i = 0;i < n;i++){
		int up = 0;
		for(int j = 0; j  < v;j++){
			if(d[a[j].f]!=INF && d[a[j].e] > (d[a[j].f] + a[j].w)){
				d[a[j].e] = d[a[j].f] + a[j].w;
				up = 1;
			}
		}
		if(i == v && !up){ //负圈
			printf("-1\n");
		}
	}
	for(int i = 1; i <= n;i++){
		printf("%d\n",d[i]);
	}

}

int main(){

	while(cin >> n >> v){
		for(int i = 0;i < v;i++){
			cin >> a[i].f >> a[i].e >> a[i].w;
		}
		int s;
		cin >> s;
		bllman_ford(s);

	}
	return 0;
}