POJ

虽说是复习，但还是要贴上，文章+1

#include <stdio.h>#include <string.h>#include <iostream>#include<algorithm>#include <vector>#include <queue>#include <string>#include <math.h>#include <stdlib.h>using namespace std;#define INF 0x3f3f3f3f#define mem(arr,a) memset(arr,a,sizeof(arr))#define N 5000+5#define pow(a) ((a)*(a))struct edge{    int u, v, w;};int par[N];edge es[N];int sum;int n, m;bool cmp(edge a, edge b){    return a.w < b.w;}void init(){    for (int i = 1; i <= n; i++)par[i] = i;}int find(int x){    if (x == par[x])return x;    return par[x] = find(par[x]);}bool same(int a, int b){    a = find(a);    b = find(b);    if (a==b)return true;    return false;}void unite(int a, int b){    a = find(a);    b = find(b);    par[a] = b;}int kruskal(){    sort(es+1, es + m+1, cmp);    for (int i = 1; i <= m; i++){        edge e = es[i];        if (!same(e.u, e.v)){            unite(e.u, e.v);            sum += e.w;        }    }    return sum;}int main(){    while (~scanf("%d", &n)){        if (n == 0)break;        scanf("%d", &m);        init();        sum = 0;        for (int i = 1; i <= m; i++){            scanf("%d%d%d", &es[i].u, &es[i].v, &es[i].w);        }        printf("%d\n", kruskal());    }}