hihocoder 第二十九周 堆优化的Prim算法

又深刻理解了一遍prim和dijkstra算法，感觉蛮棒的~

第一次自己用邻接表写，just soso~ 啊哈~

一开始被优先队列，重载运算符给卡住了~ 蛋疼~

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<queue>
#include<algorithm>
#include<map>
#include<iomanip>
#include<climits>
#include<string.h>
#include<stdlib.h>
#include<vector>
#define INF 1e7
#define MAXN 111111
using namespace std;


struct node{
    int v, w;
    bool operator < (const node& a) const {
        return w > a.w;
    }
};

vector<node> G[MAXN];
bool vis[MAXN];
int dis[MAXN];
int n, m;
priority_queue<node> q;


void Prim(node s)
{
    memset(vis, 0, sizeof(vis));
    for (int i = 0; i <= n; ++i) dis[i] = INF;
    while (!q.empty())  q.pop();
    int ans = 0;
    q.push(s);
    while (!q.empty()) {
        node u = q.top();
        q.pop();
        if (vis[u.v]) continue;
        vis[u.v] = true;
        ans += u.w;
        //cout << ans << endl;
        for (int i = 0; i < G[u.v].size(); ++i) {
            int v = G[u.v][i].v;
            if (!vis[v] && dis[v] > G[u.v][i].w) {
                dis[v] = G[u.v][i].w;
                q.push({ v, dis[v] });
            }
        }
    }
    cout << ans << endl;
}


int main()
{
    int a, b, c;
    cin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        cin >> a >> b >> c;
        G[a].push_back({ b, c });
        G[b].push_back({ a, c });
    }
    Prim({ 1, 0 });
    //system("pause");
    return 0;
}