数组循环移位

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字符串或数组的翻转，比如输入’hello’, return ‘olleh’.

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class Solution(object):
    def reverseString(self, s):
        """
        :type s: str
        :rtype: str
        """
        slist = list(s)
        def reverse(str1,index1,index2):
            while index1 < index2:
                str1[index1],str1[index2]=str1[index2],str1[index1]
                index1 += 1
                index2 -= 1
        reverse(slist,0,len(slist)-1)
        return ''.join(slist)

如果要求把字符串或数组向左或右移动k位，也可以通过reverse的方法做

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class Solution(object):
    def reverseString(self, s,k):
        """
        :type s: str
        :rtype: str
        """
        slist = list(s)
        N = len(s)
        k %= N
        def reverse(str1,index1,index2):
            while index1 < index2:
                str1[index1],str1[index2]=str1[index2],str1[index1]
                index1 += 1
                index2 -= 1
        reverse(slist,0,N-k-1)
        reverse(slist,N-k,N-1)
        reverse(slist,0,N-1)
        return ''.join(slist)