Poj(1789)，最小生成树,Prim

题目链接：http://poj.org/problem?id=1789

还是套路。

#include <stdio.h>
#include <string.h>

#define INF 0x3f3f3f3f

int maps[2005][2005];
char str[2005][2005];
int dis[2005];
bool vis[2005];
int n;

int Prim()
{
    memset(vis,false,sizeof(vis));
    for(int i=1; i<=n; i++)
        dis[i] = INF;
    int ans=0;
    dis[1] = 0;
    for(int i=1; i<=n; i++)
    {
        int tmp = INF,k=0;
        for(int j=1; j<=n; j++)
        {
            if(!vis[j]&&dis[j]<tmp)
            {
                tmp = dis[j];
                k=j;
            }
        }

        vis[k] = true;
        ans+=tmp;
        for(int i=1; i<=n; i++)
        {
            if(!vis[i]&&dis[i]>maps[k][i])
                dis[i] = maps[k][i];
        }
    }
    return ans;
}

int main()
{
    while(scanf("%d",&n),n)
    {
        for(int i=0;i<n;i++)
            scanf("%s",str[i]);

        for(int i=0;i<n;i++)
        {
            for(int j=0;j<n;j++)
            {
                int dist = 0;
                for(int k=0;k<7;k++)
                {
                    if(str[i][k]!=str[j][k])
                        dist++;
                }
                maps[i+1][j+1] = dist;
            }
        }
        printf("The highest possible quality is 1/%d.
",Prim());
    }
    return 0;
}