leetcode 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.

解法1:

class Solution(object):
    def rotateString(self, A, B):
        """
        :type A: str
        :type B: str
        :rtype: bool
        """
        """
Input: A = 'abcde', B = 'cdeab'
Output: true
A+A='abcde'+'abcde'='abcdeabcde'
check B in A+A 
        """
        s = A + A
        i = s.find(B)
        if i < 0:
            return False
        else:
            return s[i+len(B):]+s[:i] == B        

另外可以：

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