HDU 4712 Hamming Distance（随机算法）

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4712

题目大意：任意两个数按位异或后二进制中含1的个数被称为海明距离，给定n个数，求出任意其中两个最小的海明数，输入是16进制。

Sample Input

2

2

12345

54321

4

12345

6789A

BCDEF

0137F

 

Sample Output

6

7

分析：用随机数来模拟，加srand()函数，放置产生伪随机数。代码有2个。

代码1：

 # include<iostream>
 # include<cstdio>
 # include<cstring>
 # include<ctime>
 # include<cstdlib>
 # define INF 0x3f3f3f3f

 using namespace std;

 int cmp[][];
 char data[][];

 int solve(int q,int w)
 {
     int a,b,ret=;
     for(int i=; i<; i++)
     {
         char x = data[q][i];
         char y = data[w][i];
         if(x>='' && x<='')
             a = x-'';
         else
             a = x-'A' + ;
         if(y>='' && y<='')
             b = y-'';
         else
             b = y-'A' + ;
         ret += cmp[a][b];
     }
     return ret;
 }
 int main()
 {
     int i,j;
     for(i=; i<; i++)
     {
         for(j=; j<; j++)
         {
             int ans=;
             int tmp = i^j;
             for(int k=; k<; k++)
                 if((<<k) & tmp)
                     ans ++;
             cmp[i][j] = ans;
         }
     }

     int T,n;
     scanf("%d",&T);
     while(T--)
     {
         scanf("%d",&n);
         for(i=; i<=n; i++)
             scanf("%s",data[i]);
         int ans = INF;
         srand((unsigned)time(NULL));
         for(i=; i<=; i++)
         {
             int a = rand()%n + ;
             int b = rand()%n + ;
             if(a==b)
                 b= b%n+;
             int tmp = solve(a,b);
             if(tmp < ans)
                 ans = tmp;
         }
         printf("%d\n",ans);
     }
     return ;
 }

代码2：

 # include<iostream>
 # include<cstdio>
 # include<cstring>
 # include<ctime>
 # include<cstdlib>
 # define INF 0x3f3f3f3f

 using namespace std;

 int data[];

 int get_one(int x)
 {
     int ret = ;
     while(x)
     {
         ret ++;
         x = x&(x-);
     }
     return ret;
 }
 int main()
 {
     srand((unsigned)time(NULL));
     int T,n,i;
     scanf("%d",&T);
     while(T--)
     {
         scanf("%d",&n);
         for(i=; i<n; i++)
             scanf("%x",&data[i]);
         int ans = INF;
         for(i=; i>=; i--)    //好奇怪，这里从前往后循环返回WA
         {
             int a = rand()%n ;
             int b = rand()%n ;
             if(a != b)
                 ans = min(ans,get_one(data[a]^data[b]));
         }
         printf("%d\n",ans);
     }
     return ;
 }