poj_1258 prim最小生成树

#include<stdio.h>
#include<vector>
#include<queue>
#include<string.h>
#include<algorithm>
using namespace std;
#define MAX_NODE 105

struct Edge{
	int vertex;
	int dist;
	Edge(int v, int d) :
		vertex(v), dist(d){};
};
vector<vector<Edge> > gGraph;
struct Compare{
	bool operator()(const Edge& e1, const Edge& e2){
		return e1.dist > e2.dist;
	}
};

bool gVisited[MAX_NODE];

int Prim(int n){	//prim算法加堆优化
	memset(gVisited, false, sizeof(gVisited));
	//随便选择一个起点，假设从0开始
	Edge e(0, 0);
	int sum_mst = 0;
	priority_queue<Edge, vector<Edge>, Compare> pq;
	pq.push(e);
	while (!pq.empty()){
		e = pq.top();
		pq.pop();
		if (gVisited[e.vertex])
			continue;
		gVisited[e.vertex] = true;
		sum_mst += e.dist;
		for (int i = 0; i < gGraph[e.vertex].size(); i++){	//将该点连接边都加入到优先队列中，进行下一轮选择
			pq.push(gGraph[e.vertex][i]);
		}
	}
	return sum_mst;
}

int main(){
	int n, dist;
	while (scanf("%d", &n) != EOF){
		gGraph.clear();
		gGraph.resize(n);
		for (int i = 0; i < n; i++){
			for (int j = 0; j < n; j++){
				scanf("%d", &dist);
				gGraph[i].push_back(Edge(j, dist));
			}
		}
		int result = Prim(n);
		printf("%d\n", result);
	}
	return 0;
}