51nod 1212 无向图最小生成树

题目链接：http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1212

#include <stdio.h>
#include <iostream>
#include <string.h>
#include <algorithm>
#include <math.h>
#include <stack>
#include <queue>

using namespace std;
#define INF 10000000

int n, m;
int a, b, c;

int map[1010][1010], dis[1010], v[1010];

int prim(int n)
{
int i, j, k, min, sum = 0;
for (i = 1; i <= n; i++)
dis[i] = map[1][i];

memset(v, 0, sizeof(v));
v[1] = 1;
dis[1] = 0;

for (i = 2; i <= n; i++)
{
k = 1;
min = INF;
for (j = 1; j <= n; j++)
if (!v[j] && min>dis[j])
{
k = j;
min = dis[j];
}
sum += min;
v[k] = 1;
for (j = 1; j <= n; j++)
if (!v[j] && dis[j]>map[k][j])
dis[j] = map[k][j];
}
return sum;
}

int main()
{
while (scanf("%d %d", &n, &m) != EOF)
{
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
map[i][j] = INF;

while (m--)
{
scanf("%d%d%d", &a, &b, &c);
if (map[a][b] >= c)
{
map[a][b] = map[b][a] = c;
}
}
printf("%d\n", prim(n));
}
return 0;
}