POJ 1258 Agri-Net

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Prim模板

C++ Code

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#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <string.h>
#include <queue>
#include <vector>
#define MAX 101

using namespace std;

int arr[MAX][MAX];
bool vis[MAX];
int num;

struct node{
	int num;
	int v;
	bool operator<(const node &b) const{
		return v > b.v;
	}
};

int prim(int start){
	int ans = 0;
	priority_queue<node> q;
	memset(vis, false, sizeof(vis));
	node tmp;
	tmp.num = start;
	tmp.v = 0;
	q.push(tmp);
	for(int k = 0; k < num; k++){
		node cur;
		do{
			cur = q.top();
			q.pop();
		}while(vis[cur.num]);
		vis[cur.num] = true;
		ans += cur.v;
		for(int i = 0; i < num; i++){
			if(!vis[i] && arr[cur.num][i] > 0){
				node tmp;
				tmp.num = i;
				tmp.v = arr[cur.num][i];
				q.push(tmp);
			}
		}
	}
	return ans;
}

int main(){
    while(~scanf("%d", &num)){
        for(int i = 0; i < num; i++){
            for(int j = 0; j < num; j++){
                scanf("%d", &arr[i][j]);
            }
        }
        int ans = prim(0);
        printf("%d\n", ans);
    }
    return 0;
}