这里只有模板，并不作讲解，仅为路过的各位做一个参考以及用做自己复习的资料，转载注明出处。
最小生成树
Prim
/*Copyright: Copyright (c) 2018
*Created on 2018-11-05
*Author: 十甫
*Version 1.0
*Title: Prim
*Time: inf mins
*/
#include<cstdio>
#include<iostream>
#include<cstring>
#include<queue>
using namespace std;
const int maxn = 10005;
const int maxm = 10005;
int head[maxn];
struct edge {
int to, val, next;
} data[maxm * 2];
inline void add_edge(int from, int to, int val, int i) {
data[i] = (edge) {to, val, head[from]};
head[from] = i;
}
int n, m;
int dis[maxn];
bool vis[maxn];
struct node {
int dist, ord;
bool operator < (const node cmp) const {
return dist > cmp.dist;
}
};
int Prim(int p) {
int ans = 0;
memset(dis, 0x3f, sizeof(dis));
memset(vis, false, sizeof(vis));
dis[p] = 0;
priority_queue <node> q;
q.push((node) {dis[p], p});
for(int i = 1;i <= n;i++) {
while(vis[q.top().ord]) q.pop();
node tmp = q.top();
int u = tmp.ord;
q.pop();
vis[u] = true;
ans += tmp.dist;
for(int i = head[u];i;i = data[i].next) {
int v = data[i].to, k = data[i].val;
if(dis[v] > k) {
dis[v] = k;
q.push((node) {dis[v], v});
}
}
}
return ans;
}
int main() {
scanf("%d%d", &n, &m);
for(int i = 1;i <= m;i++) {
int a, b, c;
scanf("%d%d%d", &a, &b, &c);
add_edge(a, b, c, i), add_edge(b, a, c, i + m);
}
printf("%d
", Prim(1));
return 0;
}