图论--最短路--SPFA模板（能过题，真没错的模板）

 [ACM常用模板合集] 

#include<iostream>
#include<queue>
#include<algorithm>
#include<set>
#include<cmath>
#include<vector>
#include<map>
#include<stack>
#include<bitset>
#include<cstdio>
#include<cstring>
#define Swap(a,b) a^=b^=a^=b
#define cini(n) scanf("%d",&n)
#define cinl(n) scanf("%lld",&n)
#define cinc(n) scanf("%c",&n)
#define cins(s) scanf("%s",s)
#define coui(n) printf("%d",n)
#define couc(n) printf("%c",n)
#define coul(n) printf("%lld",n)
#define speed ios_base::sync_with_stdio(0)
#define Max(a,b) a>b?a:b
#define Min(a,b) a<b?a:b
#define mem(n,x) memset(n,x,sizeof(n))
#define INF  0x3f3f3f3f
#define maxn  100010
#define Ege 100000000
#define Vertex 1005
#define esp  1e-9
#define mp(a,b) make_pair(a,b)
using namespace std;
typedef long long ll;
typedef pair<int,int> PII;
struct Node
{
    int to, lat, val; //边的右端点，边下一条边，边权
};
Node edge[1000005];
int head[1005],tot,dis[1005],N,M,vis[1005];
void add(int from, int to, int dis)
{
	edge[++tot].lat = head[from];
	edge[tot].to = to;
	edge[tot].val = dis;
	head[from] = tot;

}
void spfa(int s)
{

	memset(dis, 0x3f, sizeof(dis));
	dis[0]=0;
	memset(vis, 0, sizeof(vis));
	vis[s] = 1;
	dis[s] = 0;
	queue<int>Q;
	Q.push(s);
	while (!Q.empty()) {
		int u = Q.front();
		Q.pop();
		vis[u] = 0;
		for (int i = head[u];i;i = edge[i].lat) {
			int to = edge[i].to;
			int di = edge[i].val;
			if (dis[to]>dis[u] + di) {
				dis[to] = dis[u] + di;
				if (!vis[to]) {
					vis[to] = 1;
					Q.push(to);
				}
			}
		}
	}

}
int main()
{
    int t, x;
    scanf("%d", &t);
    while (t--)
    {
        memset(head, 0, sizeof(head));
        cini(N),cini(M);
        while (M--)
        {
            int a, b, dis;
            scanf("%d %d %d", &a, &b, &dis);
            add(a, b, dis),add(b,a,dis);
        }
        cini(x);
        spfa(x);
       
    }
    return 0;
}