POJ 3259 Wormholes

/*
*POJ 3259 Wormholes
*判断负权值回路
*/
#include <cstdio>
#include <cstring>
#include <queue>

using namespace std;

#define INF 10000000
#define MAXN 600

struct ArcNode {
	int to;
	int weight;
	ArcNode *next;
};
queue<int> q;
int N, M, W;
ArcNode *list[MAXN]; //每个顶点的边链表表头指针
int in[MAXN];  //每个顶点是否在队列
int count[MAXN]; //每个顶点入队列的次数
int dist[MAXN];

bool spfa(int src)
{
	int i, u;
	ArcNode *temp;
	for (i = 1 ; i <= N; i++) {
		dist[i] = INF;
		in[i] = 0;
	}
	dist[src] = 0;  in[src] ++;
	q.push(src);
	count[src] ++;
	while ( !q.empty()) {
		u = q.front();
		q.pop();
		in[u] --;
		if (count[u] > N) //存在负权值回路
			return true;
		temp = list[u];
		while (temp != NULL) {
			int v = temp->to;
			if (dist[v] > dist[u] + temp->weight) {
				dist[v] = dist[u] + temp->weight;
				if (!in[v]) {
					q.push(v);  in[v]++;   count[v]++;
				}
			}
			temp = temp->next;
		}
	}
	return false;
}

int main()
{
	int i, T;
	int u, v, w;
	scanf("%d", &T);
	while (T--) {
		scanf("%d%d%d", &N, &M, &W);
		memset(list, 0, sizeof(list));
		memset(in, 0, sizeof(in));
		memset(count, 0, sizeof(count));
		while (!q.empty()) {
			q.pop();
		}
		ArcNode *temp;
		for (i = 1; i <= M; i++) {
			scanf("%d%d%d", &u, &v, &w);
			temp = new ArcNode;
			temp->to = v;   temp->weight = w;   temp->next = NULL;
			if (list[u] == NULL) {
				list[u] = temp;
			} else {
				temp->next = list[u];   list[u] = temp;
			}
			temp = new ArcNode;
			temp->to = u;   temp->weight = w;   temp->next = NULL;
			if (list[v] == NULL) {
				list[v] = temp;
			} else {
				temp->next = list[v];   list[v] = temp;
			}
		}
		for (i = 1; i <= W; i++) {
			scanf("%d%d%d", &u, &v, &w);
			temp = new ArcNode;
			temp->to = v;   temp->weight = -w;  temp->next = NULL;
			if (list[u] == NULL) {
				list[u] = temp;
			} else {
				temp->next = list[u];   list[u] = temp;
			}
		}
		if (spfa(1)) {
			printf("YES\n");
		} else {
			printf("NO\n");
		}
		for (i = 1; i <= N; i++) {
			temp = list[i];
			while (temp != NULL) {
				list[i] = temp->next;   delete temp;    temp = list[i];
			}
		}
	}
	return 0;
}