nyoj 城市平乱(Dijkstra)

  1 #include<iostream>
  2 #include<cstdio>
  3 #include<cstdlib>
  4 #include<cstring>
  5 #include<string>
  6 #include<queue>
  7 #include<algorithm>
  8 #include<map>
  9 #include<iomanip>
 10 #include<climits>
 11 #include<string.h>
 12 #include<cmath>
 13 #include<stdlib.h>
 14 #include<vector>
 15 #include<stack>
 16 #include<set>
 17 using namespace std;
 18 #define INF 1000000007
 19 #define MAXN 2010
 20 #define Mod 1000007
 21 #define N 100010
 22 #define NN 30
 23 #define sigma_size 3
 24 const int MAX = 1000100;
 25 const int maxn = 6e5 + 10;
 26 using namespace std;
 27 typedef long long LL;
 28 
 29 bool vis[1010];
 30 int G[1010][1010];
 31 int army[1100];
 32 int dist[1010];
 33 int n, m, p, q;
 34 int u, v, w, tmp;
 35 
 36 void Dijkstra(int src)
 37 {
 38     int min, pos;
 39     for (int i = 1; i <= m; ++i)
 40         dist[i] = G[src][i];
 41     dist[src] = 0;
 42     vis[src] = true;
 43     for (int i = 1; i <= m; ++i) {
 44         min = MAX;
 45         for (int j = 1; j <= m; ++j) {
 46             if (dist[j] < min && !vis[j]) {
 47                 min = dist[j];
 48                 pos = j;
 49             }
 50         }
 51         if (min == MAX) return;
 52         vis[pos] = true;
 53         for (int j = 1; j <= m; ++j){
 54             if (!vis[j] && dist[pos] + G[pos][j] < dist[j]) {
 55                 dist[j] = dist[pos] + G[pos][j];
 56             }
 57         }
 58     }
 59 }
 60 
 61 void run()
 62 {
 63     scanf("%d%d%d%d", &n, &m, &p, &q);
 64     memset(army,0,sizeof(army));
 65     memset(vis,0,sizeof(vis));
 66     memset(dist,0,sizeof(dist));
 67     for (int i = 0; i <= m; ++i) {
 68         for (int j = 0; j <= m; ++j) {
 69             G[i][j] = G[j][i] = MAX;
 70         }
 71     }
 72     for (int i = 0; i < n; ++i) {
 73         scanf("%d", &tmp);
 74         army[tmp] = 1;
 75     }
 76     for (int i = 1; i <= p; ++i) {
 77         scanf("%d%d%d", &u, &v, &w);
 78         if (G[u][v] > w) G[u][v] = G[v][u] = w;
 79     }
 80     Dijkstra(q);
 81     /*for (int i = 1; i <= m; ++i)
 82         cout << dist[i] << " ";
 83     cout << endl;*/
 84     int mmax = MAX;
 85     for (int i = 1; i <= m; ++i) {
 86         if (mmax > dist[i] && army[i])
 87             mmax = dist[i];
 88     }
 89     printf("%d\n",mmax);
 90     //system("pause");
 91 }
 92 
 93 int main()
 94 {
 95     int T;
 96     scanf("%d",&T);
 97     while (T--)
 98         run();
 99     return 0;
100 }