leetcode 796. Rotate String（python）

leetcode 796. Rotate String（python）

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.

解析

根据题意，就是判断在经过了 shift 操作之后的 A 和 B 是否相等，先判断其中出现的字符和数量是否相等，如果相等则对 A 进行 len(A) 次的 shift 操作，每次操作判断其与 B 是否相等，如果相等则返回 True， 如果遍历 len(A) 次之后仍不相等，则返回 False 。

解答

class Solution(object):
    def rotateString(self, A, B):
        """
        :type A: str
        :type B: str
        :rtype: bool
        """
        a = collections.Counter(A)
        b = collections.Counter(B)
        if a != b:
            return False
        n = len(A)
        while n >= 0:
            if A == B:
                return True
            else:
                n -= 1
                A = A[1:]+A[0]
        return False            	      
		

运行结果

Runtime: 16 ms, faster than 78.91% of Python online submissions for Rotate String.
Memory Usage: 13.7 MB, less than 10.19% of Python online submissions for Rotate String.

原题链接：leetcode.com/problems/ro…

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