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  • [LC] 541. Reverse String II

    Given a string and an integer k, you need to reverse the first k characters for every 2k characters counting from the start of the string. If there are less than k characters left, reverse all of them. If there are less than 2k but greater than or equal to k characters, then reverse the first k characters and left the other as original.

    Example:

    Input: s = "abcdefg", k = 2
    Output: "bacdfeg"
    

    Restrictions:

    1. The string consists of lower English letters only.
    2. Length of the given string and k will in the range [1, 10000]
    class Solution {
        public String reverseStr(String s, int k) {
            int i = 0;
            char[] charArr = s.toCharArray();
            while (i < charArr.length) {
                int j = Math.min(i + k - 1, charArr.length - 1);
                swap(i, j, charArr);
                i += 2 * k;
            }
            return new String(charArr);
        }
        
        private void swap(int i, int j, char[] charArr) {
            while (i < j) {
                char temp = charArr[i];
                charArr[i] = charArr[j];
                charArr[j] = temp;
                i += 1;
                j -= 1;
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/xuanlu/p/12143815.html
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