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：
1 # include<iostream> 2 # include<cstdio> 3 # include<cstring> 4 # include<ctime> 5 # include<cstdlib> 6 # define INF 0x3f3f3f3f 7 8 using namespace std; 9 10 int cmp[16][16]; 11 char data[100005][6]; 12 13 int solve(int q,int w) 14 { 15 int a,b,ret=0; 16 for(int i=0; i<5; i++) 17 { 18 char x = data[q][i]; 19 char y = data[w][i]; 20 if(x>='0' && x<='9') 21 a = x-'0'; 22 else 23 a = x-'A' + 10; 24 if(y>='0' && y<='9') 25 b = y-'0'; 26 else 27 b = y-'A' + 10; 28 ret += cmp[a][b]; 29 } 30 return ret; 31 } 32 int main() 33 { 34 int i,j; 35 for(i=0; i<16; i++) 36 { 37 for(j=0; j<16; j++) 38 { 39 int ans=0; 40 int tmp = i^j; 41 for(int k=0; k<4; k++) 42 if((1<<k) & tmp) 43 ans ++; 44 cmp[i][j] = ans; 45 } 46 } 47 48 int T,n; 49 scanf("%d",&T); 50 while(T--) 51 { 52 scanf("%d",&n); 53 for(i=1; i<=n; i++) 54 scanf("%s",data[i]); 55 int ans = INF; 56 srand((unsigned)time(NULL)); 57 for(i=1; i<=60000; i++) 58 { 59 int a = rand()%n + 1; 60 int b = rand()%n + 1; 61 if(a==b) 62 b= b%n+1; 63 int tmp = solve(a,b); 64 if(tmp < ans) 65 ans = tmp; 66 } 67 printf("%d ",ans); 68 } 69 return 0; 70 }
代码2：
1 # include<iostream> 2 # include<cstdio> 3 # include<cstring> 4 # include<ctime> 5 # include<cstdlib> 6 # define INF 0x3f3f3f3f 7 8 using namespace std; 9 10 int data[100005]; 11 12 int get_one(int x) 13 { 14 int ret = 0; 15 while(x) 16 { 17 ret ++; 18 x = x&(x-1); 19 } 20 return ret; 21 } 22 int main() 23 { 24 srand((unsigned)time(NULL)); 25 int T,n,i; 26 scanf("%d",&T); 27 while(T--) 28 { 29 scanf("%d",&n); 30 for(i=0; i<n; i++) 31 scanf("%x",&data[i]); 32 int ans = INF; 33 for(i=100005; i>=0; i--) //好奇怪，这里从前往后循环返回WA 34 { 35 int a = rand()%n ; 36 int b = rand()%n ; 37 if(a != b) 38 ans = min(ans,get_one(data[a]^data[b])); 39 } 40 printf("%d ",ans); 41 } 42 return 0; 43 }