POJ 2395 Out of Hay（MST）

【题目链接】http://poj.org/problem?id=2395

【解题思路】找最小生成树中权值最大的那条边输出，模板过的，出现了几个问题，开的数据不够大导致运行错误，第一次用模板，理解得不够深厚且模板有错误导致提交错误

 

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<queue>
#include<algorithm>
#define INF 1000000002
#define MAXN 2002
#define SIZE 20200

using namespace std;

int eh[MAXN], tot, dist[MAXN];
bool visit[MAXN];
int n, m;
struct Edge{
    int v, u, cost, next;
    Edge(){}
    Edge(int a, int b, int c, int d){
        v = a, u = b, cost = c, next = d;
    }
    Edge(int a, int b){v = a, cost = b;}
    bool operator < (const Edge &x) const{
        return cost > x.cost;
    }
};
struct Edge edge[SIZE];

int prim(int s)
{
    for(int i = 1; i <= n; ++i) visit[i] = false, dist[i] = INF;
    dist[s] = 0;
    priority_queue<Edge> que;
    que.push(Edge(s, 0));
    int ans = 0;
    while(!que.empty())
    {
        Edge tmp = que.top();
        que.pop();
        int u = tmp.v, cost = tmp.cost;
        if(visit[u]) continue;
        if(cost > ans) ans = cost; 
        visit[u] = true;
        for(int i=eh[u]; i != -1; i = edge[i].next)
        {
            int v = edge[i].u;
            if(!visit[v] && dist[v] > edge[i].cost)
            {
                dist[v] = edge[i].cost;
                que.push(Edge(v, dist[v]));
            }
        }
    }
    return ans;
}

void addedge(int a, int b, int c)
{
    Edge e = Edge(a, b, c, eh[a]);
    edge[tot] = e;
    eh[a] = tot++;
}

void init()
{
    tot = 0;
    memset(eh, -1, sizeof(eh));
}

int main()
{
    scanf("%d%d", &n, &m);
    init();
    for(int i = 1; i <= m; ++i)
    {
        int u, v, cost;
        scanf("%d%d%d", &u, &v, &cost);
        addedge(v, u, cost);
        addedge(u, v, cost); 
    }
    printf("%d
", prim(1));
    return 0;
}