Truck History （最小生成树）

prim或kruscal都可以

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <algorithm>
#define INF 0x3f3f3f3f
using namespace std;
char g[2005][8];
int grid[2005][2005],dist[2005],visit[2005],n;
int dis(int i,int j)
{
    int count=0,k;
    for(k=0;k<7;k++)
        if(g[i][k]!=g[j][k])
        count++;
    return count;
}
int prime()
{
    int num=1,k,i,ans=0,minc;
    memset (visit,0,sizeof(visit));
    for (i = 1; i <= n; i++)
        dist[i] = grid[1][i];
    visit[1]=1;
    dist[1]=0;
    while(num++<n)
    {
        minc=INF;
        for (i=1;i<=n;i++)
            if(!visit[i] && dist[i]<minc)
            minc=dist[k=i];
        visit[k]=1;
        ans+=dist[k];
        for (i=1;i<=n;i++)
            if(!visit[i])
               dist[i]=min(dist[i],grid[k][i]);
    }
    return ans;
}
int main()
{
    int i,j;
    while ( scanf("%d",&n)!=EOF && n)
    {
        for(i=1;i<=n;i++)
            scanf("%s",g[i]);
        for (i=1;i<=n;i++)
            for(j=i+1;j<=n;j++)
                grid[i][j]=grid[j][i]=dis(i,j);
        printf("The highest possible quality is 1/%d.\n",prime());
    }
	return 0;
}