HDU 1879 继续畅通工程

基础 Kruskal

#include <iostream>
#include <stdio.h>
using namespace std;
const int MAXN = 101;

struct E{
    int x,y;
    int weight;
};

E edge[MAXN*MAXN/2];
int G[MAXN][MAXN];
int father[MAXN];

int cmp(const void *d1, const void *d2){
    return (*(E*)d1).weight - (*(E*)d2).weight;
}

void makeSet(int n){
    for(int i = 0; i <= n;i++)
        father[i] = i;
}

int find(int x){
     if(x != father[x])
        father[x] = find(father[x]);
    return father[x];
}

void merge(int x, int y){
    x = find(x);
    y = find(y);
    if(x > y)
        father[x] = y;
    else
        father[y] = x;
}
int main(){
    int n;
    int x,y,weight,statu,cost;
    while(cin >> n , n){
        makeSet(n);
        cost = 0;
        for(int i = 1; i <= n*(n-1)/2; i++){
            scanf("%d%d%d%d",&edge[i].x,&edge[i].y,&edge[i].weight,&statu);
            if(statu == 1){
                int xx = find(edge[i].x);
                int yy = find(edge[i].y);
                if(xx != yy)
                    merge(xx,yy);
            }
        }
        qsort(edge+1,n*(n-1)/2,sizeof(E),cmp);    //edge + 1
        for(int i = 1; i <= n*(n-1)/2 ;i++){
            int xx = find(edge[i].x);
            int yy = find(edge[i].y);
            if(xx != yy){
                merge(xx,yy);
                cost += edge[i].weight;
            }
        }
        cout << cost << endl;
    }
    return 0;
}