POJ T1258 Agri-Net

                                     POJ T1258 Agri-Net

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题解：

  因为给的是N*N的矩阵，所以初始化都省去了，直接上Prim模版......

 

代码：

#include<cstdio>
#include<algorithm>
#define maxn 105
#define INF 0x3f3f3f3f
using namespace std;

int n,sum,dis[maxn];
int maps[maxn][maxn];
bool vis[maxn];

void init(){
	sum = 0;
	for(int i = 1; i <= n ; i++){
		dis[i] = INF;
		vis[i] = false;
		/*for(int j = 1; j <= i; j++)
		    i == j ? maps[i][j] = 0 : maps[i][j] = maps[j][i] = INF;*/
	}
}

void Prim(int s){
	dis[s] = 0;
	for(int i = 1; i <= n ; i++){
		int p = 0, minn = INF;
		for(int j = 1; j <= n; j++){
			if(!vis[j] && minn > dis[j]){
				p = j;
				minn = dis[j];
			}
		}
		vis[p] = true;
		sum += dis[p];
		for(int j = 1; j <= n ; j++){
			if(!vis[j] && dis[j] > maps[p][j])
			    dis[j] = maps[p][j];
		}
	}
}

int main(){
	while(~scanf("%d",&n)){
	init();
	for(int i = 1; i <= n; i++)
	    for(int j = 1; j <= n ; j++)
	       scanf("%d",&maps[i][j]);
	Prim(1);
	printf("%d\n",sum);
    }
	return 0;
}