POJ1789

poj1789.cpp

#include <cstdio>
#include <ctime>
#include <cstdlib>
#include <iostream>
#include <cstring>
#include <vector>
#include <fstream>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <string>
#define MAX(a,b) (a>b?a:b)
#define sd(x) scanf("%d",&x)
#define sdd(a,b) scanf("%d%d",&a,&b)
#define sddd(a,b,c) scanf("%d%d%d",&a,&b,&c)
#define slflf(x,y) scanf("%lf%lf",&x,&y)
#define abs(x) (x<0?(-x):x)
#define MAX(a,b) (a>b?a:b)
#define MIN(a,b) (a<b?a:b)
using namespace std;

const int dsj_lenth = 2005;
char types[dsj_lenth][8];

int dsj[dsj_lenth];

void init()
{
    for (int i=0; i<dsj_lenth; i++) dsj[i]=i;
}

int Find(int x)
{
    return dsj[x]==x?x:dsj[x]=Find(dsj[x]);
}

inline void Union(int a,int b)
{
    dsj[a]=b;
}


struct road
{
    int u,v,w;
} r[dsj_lenth*dsj_lenth];

bool cmp(road a,road b)
{
    return a.w<b.w;
}

int calculateDistance(char *a,char *b)
{
    int cnt=0;
    for (int i=0;i<7;i++) if(a[i]!=b[i]) cnt++;
    return cnt;
}

int main()
{
    int n;
    while(~sd(n) && n)
    {
        getchar();
        init();
        int cnt=0;
        for (int i=0;i<n;i++) gets(types[i]);
        for (int i=0;i<n;i++)
        {
            for (int j=i+1;j<n;j++)
            {
                r[cnt].u=i;
                r[cnt].v = j;
                r[cnt++].w = calculateDistance(types[i],types[j]);
            }
        }
        sort(r,r+cnt,cmp);
        int ans=0,built=0;
        for (int i=0;i<cnt;i++)
        {
            int fa = Find(r[i].u),fb = Find(r[i].v);
            if (fa != fb)
            {
                Union(fa,fb);
                built++;
                ans += r[i].w;
            }
            if (built==n-1) break;
        }
        printf("The highest possible quality is 1/%d.\n",ans);
    }
    return 0;
}