救命，就A了最后一个点，其他的全部RE(Prim)

#include <iostream>
#include <cstdio>
#include <vector>
#include <cstring>
using namespace std;
const int N = 5005, INF = 0x3f3f3f3f;
int n, m, g[N][N], dist[N], vis[N];
int prim() {
    memset(dist, 0x3f, sizeof dist);
    int res = 0;
    vis[1] = 1;
    for (int i = 0; i < n; i ++) {
        int t = -1;
        for (int j = 1; j <= n; j ++)
            if (!vis[j] && (t == -1 || dist[t] > dist[j]))
                t = j;
        if (i && dist[t] == INF) return INF;
        if (i) res += dist[t];
        for (int j = 1; j <= n; j ++)
            dist[j] = min(dist[j], g[t][j]);
        vis[t] = 1;
    }
    return res;
}
int main() {
    scanf("%d%d", &n, &m);
    memset(g, 0x3f, sizeof g);
    while (m --) {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        g[a][b] = min(g[a][b], c);
        g[b][a] = min(g[b][a], c);
    }
    int k = prim();
    if (k == INF) printf("orz");
    else printf("%d", k);
    return 0;
}