事实证明，Prim中 $d$ 数组似乎没啥用……

下面的程序好像也能过

#include <bits/stdc++.h>
using namespace std;
#define MAXN 100001
struct edge {
	int to, w, nex;
} Edge[MAXN << 2];
int head[5005], tot, sum, cnt, vis[5005], n, m;
void add(int u, int v, int w) {
	Edge[cnt].nex = head[u];
	Edge[cnt].to = v;
	Edge[cnt].w = w;
	head[u] = cnt++;
}
struct node {
	int pos, dis;
	bool operator < (const node &x) const {
		return dis > x.dis;
	}
};
priority_queue <node> q;
void prim() {
	node temp;
	temp.dis = 0, temp.pos = 1;
	q.push(temp);
	while (!q.empty() && tot < n) {
		int u = q.top().pos, w = q.top().dis;
		q.pop();
		if (vis[u]) continue;
		tot++, sum += w;
		vis[u] = 1;
		for (int i = head[u]; i != -1; i = Edge[i].nex) {
			temp.dis = Edge[i].w, temp.pos = Edge[i].to;
			q.push(temp);
		}
	}
}
int main() {
	memset(head, -1, sizeof(head));
	int a1, a2, a3;
	cin >> n >> m;
	for (int i = 1; i <= m; i++) {
		cin >> a1 >> a2 >> a3;
		add(a1, a2, a3);
		add(a2, a1, a3);
	}
	prim();
	if (tot == n) cout << sum;
	else cout << "orz";
}