POJ 1258 Agri-Net 【最小生成树入门题目】

题意;

给出各个点之间的距离，求最小生成树。krual和prim都可以。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#define mx 105
using namespace std;
int fa[mx],sum;
int n,ce;
struct aa{
	int x,y,qu;
}ma[mx*mx];    //结构体数组开成2*mx大小，感觉自己是个智障 
void init(){
//	memset(vis, 0, sizeof(vis));
	for(int i = 1; i < mx; i++ )
		fa[i] = i;
	sum=ce=0;
}
bool cmp(aa a,aa b){
	return a.qu<b.qu;
}
int find(int x){
	return x == fa[x] ? x : fa[x] = find(fa[x]);
}

int main(){
	while(scanf("%d",&n)!=EOF){
		init();
		for(int i = 1; i <=n; i++)
			for(int j=1; j <= n; j++){
				ma[ce].x = i;
				ma[ce].y = j;
				scanf("%d",&ma[ce].qu);
				ce++;
			}
		sort(ma,ma+ce,cmp);
		for(int i = 0; i < ce; i++){
			int x = ma[i].x,y = ma[i].y, qu = ma[i].qu;
			int a=find(x),b=find(y);
			if(a == b) continue;
			else{
				fa[a] = b;
				sum += qu; 
			}
		}
		cout<<sum<<endl; 
		
	}
	return 0;
}

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