hdu2680

设置虚拟的点0，让他与所有的起点相连距离为0 就相当与从0点出发 找最短路；#include <iostream>#include <cstdio>#include <cstring>#include <queue>using namespace std;const int _max = 0x3f3f3f3f;const int maxn = 1000+10;int map[maxn][maxn];bool visit[maxn];int dist[maxn];int n, m, des;void SPFA(){    queue<int>q;    for(int i = 0; i <= n; i++)        dist[i] = _max;    dist[0] = 0;    visit[0] = true;    q.push(0);    while(!q.empty())    {        int cur = q.front();        q.pop();        visit[cur] = false;        for(int i = 0; i <= n; i++)            if(dist[i]>dist[cur]+map[cur][i])            {                dist[i] = dist[cur]+map[cur][i];                if(!visit[i])                {                    q.push(i);                    visit[i] = true;                }            }    }    if(dist[des]<_max)        printf("%d\n", dist[des]);    else printf("-1\n");}int main(){    while(scanf("%d%d%d", &n, &m, &des)!=EOF)    {        for(int i = 0; i <= n; i++)            for(int j = 0; j <= n; j++)                map[i][j] = _max;        for(int i = 1; i <= m; i++)        {            int u, v, w;            scanf("%d%d%d", &u, &v, &w);            if(map[u][v] > w) map[u][v] = w;        }        int f;        scanf("%d", &f);        for(int i = 1; i <= f; i++)        {            int v;            scanf("%d", &v);            map[0][v] = 0;        }        memset(visit, false, sizeof(visit));        SPFA();    }}