Rotate String【判断一个字符串是否为另一个字符串的偏转】

PROBLEM:

We are given two strings, A and B.

A shift on A consists of taking string A and moving the leftmost character to the rightmost position. For example, if A = 'abcde', then it will be 'bcdea' after one shift on A. Return True if and only if A can become B after some number of shifts on A.

Example 1:
Input: A = 'abcde', B = 'cdeab'
Output: true

Example 2:
Input: A = 'abcde', B = 'abced'
Output: false

Note:

• A and B will have length at most 100.

SOLVE:

class Solution {
public:
    bool rotateString(string A, string B) {
        return A.size()==B.size()&&(A+A).find(B)!=string::npos;
    }
};

def rotateString(self, A, B):        
    return len(A) == len(B) and B in A + A