topic:
Write a function whose function is to reverse the input string. The input string is given as a character array char [].
Don't allocate extra space to another array, you must modify the input array in place and use O (1) extra space to solve this problem .
You can assume that all characters in the array are printable characters in the ASCII code table.
Example 1:
输入：["h","e","l","l","o"]
输出：["o","l","l","e","h"]
示例 2：
输入：["H","a","n","n","a","h"]
输出：["h","a","n","n","a","H"]
Source: LeetCode
Link: https://leetcode-cn.com/problems/reverse-string
answer:
I used parity in the beginning, but then I do n’t think it ’s necessary.
class Solution { public void reverseString(char[] s) { int len = s.length; if (s.length > 0) { int center = len / 2; for (int i = 0; i < center; i++) { char left = s[i]; s [i] = s [len - 1 - i]; s[len - 1 - i] = left; } // 偶数 // if (center && 1 == 0) { // for (int i = 0; i < center; i++) { // char left = s[i]; // s[i] = s[len - 1 - i]; // s[len - 1 -i] = left; // } // } else { // for (int i = 0; i < center; i++) { // char left = s[i]; // s[i] = s[len - 1 - i]; // s[len - 1 -i] = left; // } // } } } }
Other people's writing:
for (int i = 0, j = s.length-1; i <= j; i++, j--){ char a = s[i]; s[i] = s[j]; s[j] = a; } Author: zyfsuzy