zoj（1586）最小生成树

题目:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1586

#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <string>
#include <iostream>
using namespace std ;
const int maxn = 1005;
const int inf = 0xffffff;
int edge[maxn][maxn];
int lowcost[maxn];
int used[maxn];
int adpter[maxn];
int n;
void prim(){
    int sum = 0;
    for(int i = 1;i < n;i++){
        lowcost[i] = edge[0][i];
        used[i] = 0;
    }
    lowcost[0] = 0;
    for(int i = 1;i < n;i++){
        int k = -1;
        for(int j = 1;j < n;j++){
            if(used[j] != -1&&(k == -1||lowcost[j]<lowcost[k]))
                k = j;
        }
        //printf("%d %d %d\n",used[k],k,lowcost[k]);
        sum += lowcost[k];
        used[k] = -1;
        for(int j = 1;j < n;j++){
            if(used[j] != -1 && edge[k][j] < lowcost[j]){
                lowcost[j] = edge[k][j];
                used[j] = k;
            }
        }
    }
    printf("%d\n",sum);
}
int main(){
    int t;
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        for(int i = 0;i < n;i++)
            scanf("%d",adpter+i);
        for(int i = 0;i < n;i++){
            for(int j = 0;j < n;j++){
                scanf("%d",&edge[i][j]);
                if(i == j)
                    edge[i][j] = inf;
                else
                    edge[i][j] += (adpter[i] + adpter[j]);
            }
        }
        prim();
    }
    return 0 ;
}