func_code_string: #include <bits/stdc++.h>   using namespace std;   struct MaxFlow {     int T;     struct node {       int to, nxt, cap;     } ed[811 * 811 << 1];     int head[811], cur[811], cnt, ans;     int h[811];     void addedge(int u, int v, int cap) {       ed[cnt].to = v, ed[cnt].cap = cap, ed[cnt].nxt = head[u], head[u] = cnt++;       ed[cnt].to = u, ed[cnt].cap = 0, ed[cnt].nxt = head[v], head[v] = cnt++;     }     bool bfs() {       memset(h, -1, sizeof(h));       queue<int> q;       h[1] = 0, q.push(1);       while (!q.empty()) {         int now = q.front();         q.pop();         for (int i = head[now]; ~i; i = ed[i].nxt) {           if (ed[i].cap && h[ed[i].to] == -1) {             h[ed[i].to] = h[now] + 1;             q.push(ed[i].to);           }         }       }       return h[T] != -1;     }     int dfs(int x, int f) {       if (x == T || f == 0) return f;       int w, used = 0;       for (int i = cur[x]; ~i; i = ed[i].nxt) {         if (h[ed[i].to] == h[x] + 1) {           w = f - used;           w = dfs(ed[i].to, min(w, ed[i].cap));           ed[i].cap -= w;           ed[i ^ 1].cap += w;           if (ed[i].cap) cur[x] = i;           used += w;           if (used == f) return f;         }       }       if (!used) h[x] = -1;       return used;     }     void dinic() {       while (bfs()) {         for (int i = 1; i <= T; i++) {           cur[i] = head[i];         }         ans += dfs(1, 100000005);       }     }     void init(int t) {       memset(head, -1, sizeof(head));       ans = cnt = 0;       T = t;     }   } flow;   int dis[811][811], st[811];   int main() {     int v, e, n, k;     scanf( %d%d%d%d , &v, &e, &n, &k);     for (int i = 1; i <= n; i++) scanf( %d , &st[i]);     for (int i = 1; i <= v; i++)       for (int j = i + 1; j <= v; j++) dis[i][j] = dis[j][i] = 100000005;     for (int i = 1; i <= e; i++) {       int a, b, c;       scanf( %d%d%d , &a, &b, &c);       dis[a][b] = min(dis[a][b], c);       dis[b][a] = dis[a][b];     }     for (int x = 1; x <= v; x++) {       for (int i = 1; i <= v; i++) {         for (int j = 1; j <= v; j++) {           dis[i][j] = min(dis[i][x] + dis[x][j], dis[i][j]);         }       }     }     int l = 0, r = 1731311, ct = -1;     while (l <= r) {       int mid = l + r >> 1;       flow.init(1 + n + v + 2);       for (int i = 1; i <= n; i++) {         flow.addedge(1, i + 1, 1);         for (int j = 1; j <= v; j++) {           if (dis[st[i]][j] <= mid) {             flow.addedge(i + 1, 1 + j + n, 1);           }         }       }       for (int i = 1; i <= v; i++) flow.addedge(1 + i + n, 1 + v + n + 1, 1);       flow.addedge(1 + v + n + 1, 1 + v + n + 2, k);       flow.dinic();       if (flow.ans == k) {         ct = mid;         r = mid - 1;       } else         l = mid + 1;     }     printf( %d n , ct);     return 0;   }   