[leetcode]344. Reverse String

最新推荐文章于 2024-01-01 10:31:38 发布

原创最新推荐文章于 2024-01-01 10:31:38 发布 · 110 阅读

0 ·

CC 4.0 BY-SA版权

leetcode刷题笔记专栏收录该内容

17 篇文章

订阅专栏

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通过交换首尾元素的方式逐步实现字符串的反转，特别强调了算法的空间效率和对ASCII字符的支持。

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"]

Solution:

class Solution {
    public void reverseString(char[] s) {
        if(s == null) {
            return;
        }
        int len = s.length;
        for(int i = 0; i < len/2; i ++) { 
            swap(s,i,len-1-i);
              
        }
    }
    public void swap(char[] s, int i, int j) {
        char tmp = s[i];
        s[i] = s[j];
        s[j] = tmp;
    }
}