Reverse String

flyatcmu

于 2018-12-25 13:20:06 发布

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分类专栏： String

本文链接：https://blog.youkuaiyun.com/u013325815/article/details/85246393

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本文详细介绍了一种在不使用额外空间的情况下，对字符数组进行原地反转的算法。通过实例演示了如何利用swap交换技巧，对输入的字符串进行高效反转，同时保持O(1)的额外内存消耗。

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Write a function that reverses a string. The input string is given as an array of characters char[].

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

You may assume all the characters consist of printable ascii characters.

Example 1:

Input: ["h","e","l","l","o"]
Output: ["o","l","l","e","h"]

Example 2:

Input: ["H","a","n","n","a","h"]
Output: ["h","a","n","n","a","H"]

思路：swap；

class Solution {
    public void reverseString(char[] s) {
        if(s == null || s.length == 0) {
            return;
        }
        int i = 0; int j = s.length - 1;
        while(i <= j) {
            char temp = s[i];
            s[i] = s[j];
            s[j] = temp;
            i++;
            j--;
        }
    }
}