POJ1258Agri-Net

#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <algorithm>
using namespace std;

const int maxm = 5500;
const int maxn = 110;
int fa[maxn];
int N;

struct edge {
    int x, y, w;
};
bool cmp(edge a, edge b) {
    return a.w < b.w;
}
vector<edge> v;
int getfather(int x) {
    if(x==fa[x]) return x;
    else return fa[x] = getfather(fa[x]);
}

int krucal() {
    int cnt = N;
    int ans = 0;
    int edgeSize = v.size();
    for(int i = 1; i <= N; i++) fa[i] = i;
    for(int i=0; i < edgeSize; i++) {
        int f1 = getfather(v[i].x);
        int f2 = getfather(v[i].y);
        if(f1 != f2) {
            fa[f1] = f2;
            cnt--;
            ans += v[i].w;
            if(cnt==1) break;
        }
    }
    return ans;
}

int main()
{
    edge tmp;
    int w;
    while(scanf("%d", &N)!=EOF) {
        v.clear();
        for(int i = 1; i <= N; i++) {
            for(int j = 1; j <= N; j++) {
                scanf("%d", &w);
                if(i!=j || w>0) {
                    tmp.x = i;
                    tmp.y = j;
                    tmp.w = w;
                    v.push_back(tmp);
                }
            }
        }
        sort(v.begin(), v.end(), cmp);
        int result = krucal();
        printf("%d
", result);
    }
    return 0;
}