hdu 1879 继续畅通工程

点击打开链接1879

/*
1思路：最小生成树+kruskal
2注意把已经建好的合并
*/
#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
#define MAXN 110
#define INF 0XFFFFFFF

int n , m , ans;
int father[MAXN];
int rank[MAXN];
struct Edge{
    int x;
    int y;
    int value;
    int state;
}e[10000];

bool cmp(Edge e1 , Edge e2){
     return e1.value < e2.value;
}

void init_Set(){
     for(int i = 1 ; i <= n ; i++){
        father[i] = i;
        rank[i] = 1;
     }
}

int find_Set(int x){
    int tmp = x;
    while(father[tmp] != tmp)
        tmp = father[tmp];
    while(father[x] != tmp){
        int tmp_x = father[x];
        father[x] = tmp;
        x = tmp_x;
    }
    return tmp;
}

void union_Set(int x , int y){
     if(rank[x] >= rank[y]){
        rank[x] += rank[y];
        father[y] = x;
     }
     else{
        rank[y] += rank[x];
        father[x] = y;
     } 
}

void kruskal(){
     sort(e , e+m , cmp);
     ans = 0;
     for(int i = 1 ; i <= m ; i++){
        int root_x = find_Set(e[i].x);
        int root_y = find_Set(e[i].y);
        if(root_x != root_y){
          if(!e[i].state)
            ans += e[i].value;
          union_Set(root_x , root_y);
        }
     }
     printf("%d\n" , ans);
}

int main(){
    //freopen("input.txt" , "r" , stdin);
    while(scanf("%d" , &n) , n){
        m = n*(n-1)/2;
        init_Set();
        for(int i = 1; i <= m ; i++){
           scanf("%d%d%d%d" , &e[i].x , &e[i].y , &e[i].value , &e[i].state);
           if(e[i].state)
             union_Set(find_Set(e[i].x) , find_Set(e[i].y));
        }
        kruskal();
    }     
    return 0;
}