codeforces 559B Equivalent Strings 分治归并

Equivalent Strings

 

Today on a lecture about strings Gerald learned a new definition of string equivalency. Two strings a and b of equal length are called equivalent in one of the two cases:

1. They are equal.
2. If we split string a into two halves of the same size a1 and a2, and string binto two halves of the same size b1 and b2, then one of the following is correct:
   1. a1 is equivalent to b1, and a2 is equivalent to b2
   2. a1 is equivalent to b2, and a2 is equivalent to b1

As a home task, the teacher gave two strings to his students and asked to determine if they are equivalent.

Gerald has already completed this home task. Now it's your turn!

Input

The first two lines of the input contain two strings given by the teacher. Each of them has the length from 1 to 200 000 and consists of lowercase English letters. The strings have the same length.

Output

Print "YES" (without the quotes), if these two strings are equivalent, and "NO" (without the quotes) otherwise.

Examples

Input

aaba
abaa

Output

YES

Input

aabb
abab

Output

NO

Note

In the first sample you should split the first string into strings "aa" and "ba", the second one — into strings "ab" and "aa". "aa" is equivalent to "aa"; "ab" is equivalent to "ba" as "ab" = "a" + "b", "ba" = "b" + "a".

In the second sample the first string can be splitted into strings "aa" and "bb", that are equivalent only to themselves. That's why string "aabb" is equivalent only to itself and to string "bbaa".

思路：

STL string的函数真TM好用！！！

代码：

#include<cstdio>
#include<string>
#include<cstring>
#include<iostream>
using namespace std;
const int maxn = (int)2e6 + 10;
string s1,s2;

string opt(string s)
{
    int len = s.size();
    if (len & 1) return s;
    string s1 = opt(s.substr(0,len / 2));
    string s2 = opt(s.substr(len / 2,len / 2));
    return s1 >= s2 ? s2 + s1 : s1 + s2;  
}
int main()
{
    s1.resize(maxn);
    s2.resize(maxn);  
    cin>>s1>>s2;
    string a,b;
    a = "YES",b = "NO";
    printf("%s\n",opt(s1) == opt(s2) ? a.c_str() : b.c_str());//s.c_str()使string以printf输入
    return 0;
}