nyoj-115-城市平乱（dijkstra算法）

 题目链接

 /*
     Name:nyoj-115-城市平乱
     Copyright:
     Author:
     Date: 2018/4/25 17:28:06
     Description:
     dijkstra模板题
     枚举从部队所在的城市到叛乱城市取最小值
 */
 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <cmath>
 using namespace std;
 const int MAXN = , INF= 0x3f3f3f3f;
 int dis[MAXN], g[MAXN][MAXN], N, M, P, Q, army[MAXN], src;
 bool v[MAXN];

 void dijkstra() {
     int N = M;
     for (int i=; i<=N; i++) dis[i] = INF;
     dis[src] = ;
     memset(v, , sizeof(v));
     for (int i=; i<=N; ++i) {
         int mark =-, mindis=INF;
         for (int j=; j<=N; j++) {
             if(!v[j] && dis[j]<mindis) {
                 mindis = dis[j];
                 mark = j;
             }
         }
         v[mark] = ;
         for (int j=; j<=N; j++) {
             if (!v[j]) {
                 dis[j] = min(dis[j], dis[mark] + g[mark][j]);
             }
         }
     }
 }
 int main()
 {
     int t;
     cin>>t;
     while (t--) {
         memset(g, 0x3f, sizeof(g));
         memset(army, , sizeof(army));
         cin>>N>>M>>P>>Q;
          for (int i=; i<N; i++) {
              cin>>army[i];
          }
          for (int i=; i<P; i++) {
              int x, y, cost;
              cin>>x>>y>>cost;
             if (g[x][y]  < cost) continue;
             g[x][y] = cost;
             g[y][x] = cost;
          }
          int mindis = 0x3f3f3f3f;
          for (int i=; i<N; i++) {
              memset(dis, , sizeof(dis));
              src = army[i];
              dijkstra();
              mindis = min(mindis, dis[Q]);
          }
          cout<<mindis<<endl;
     }
     return ;
 }