---
title: 'LeetCode 344. Reverse String'
disqus: hackmd
---

# LeetCode 344. Reverse String

## Description

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

You must do this by modifying the input array in-place with O(1) extra memory.

## Example

Input: s = ["h","e","l","l","o"]
Output: ["o","l","l","e","h"]
## Constraints

1 <= s.length <= 10^5^
s[i] is a printable ascii character.

## Answer

此題為普通的字串反轉，抓頭尾交換，然後loop一增一減，當頭和尾交錯即可得解。

//2021_11_16
void reverseString(char* s, int sSize) {
    char *head = s, *tail = s + sSize - 1, temp = '\0';
    while(head < tail){
        temp = *head;
        *head = *tail;
        *tail = temp;
        head++;
        tail--;
    }
}

## Link
https://leetcode.com/problems/reverse-string/
###### tags: `Leetcode`