poj 1635

有根树同构。参考论文《hash在。。。。》

 #include <iostream>
 #include <fstream>
 #include <algorithm>
 #include <cstring>
 #include <climits>
 #include <cmath>

 using namespace std;

 const int leaf_hash=;
 const int pt=;
 const int qt=;
 char str1[], str2[];
 char *p;

 int Hash()
 {
     int sum=;
     if(*(p)==''&&*(p-)==''){
         p++;
         //cout<<"leaf_hash="<<endl;
         return leaf_hash;
     }
     while(*p!='\0' && *p++ == '')//这个巧妙的循环,把子节点的hash值都加给了父节点,作为父节点的hash值
     {
         //cout<<"for"<<endl;
         sum = (sum*(pt^Hash()))%qt;
     }
 //    printf("sum==%d\n",sum);
     return sum;
 }

 int main()
 {
 //    freopen("input.txt", "r", stdin);
     int T;
     scanf("%d", &T);
     while(T--)
     {
         scanf("%s%s", str1, str2);
         p = str1;
         int a = Hash();
         p = str2;
         //cout<<a<<endl;
         int b = Hash();
         //cout<<b<<endl;
         if(a == b)
         {
             puts("same");
         }
         else
         {
             puts("different");
         }
     }
     return ;
 }