[LeetCode&Python] Problem 796. Rotate String

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(object):
    def rotateString(self, A, B):
        """
        :type A: str
        :type B: str
        :rtype: bool
        """
        if A and B:
            if len(A)!=len(B):
                return False
            for i in range(len(A)):
                if A[i+1:]+A[:i+1]==B:
                    return True
            return False
        if A and B=="":
            return False
        if A=="" and B:
            return False
        return True