poj 1258 Agri-Nets

#include <iostream>
#include <cstring>

using namespace std;

#define maxn 100+10
#define max 100000

int graph[maxn][maxn];
bool visited[maxn];
int dis[maxn];
int nodes;

int prime(int start){
	
	memset(visited,false,sizeof(visited));
	for(int i=1;i<=nodes;i++)
		dis[i] = max;

	dis[1] = 0;
	int ans = 0;

	for(int i=1;i<=nodes;i++){
		int k,temp = 1<<20;
		for(int j=1;j<=nodes;j++){
			if(!visited[j] && dis[j] < temp){
				temp = dis[j];
				k = j;
			}
		}
		ans += dis[k];
		visited[k] = true;

		for(int j=1;j<=nodes;j++)
			if(!visited[j] && dis[j] > graph[k][j])
				dis[j] = graph[k][j];

	}
	return ans;

}

int main()
{
	while(cin>>nodes){
		for(int i=1;i<=nodes;i++)
			for(int j=1;j<=nodes;j++){
				cin>>graph[i][j];
				graph[j][i] = graph[i][j];
			}
		cout<<prime(1)<<endl;
	}
	return 0;
}