LeetCode #796 - Rotate String

题目描述：

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.

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