leetcode344：反转字符串（reverse-string）

[Carlos Wei (Haochen)]

问题描述

_reverse-string_344.c

编写一个函数，其作用是将输入的字符串反转过来。输入字符串以字符数组 s 的形式给出。

不要给另外的数组分配额外的空间，你必须原地修改输入数组、使用 O(1) 的额外空间解决这一问题。

示例 1：
输入：s = ["h","e","l","l","o"]
输出：["o","l","l","e","h"]

示例 2：
输入：s = ["H","a","n","n","a","h"]
输出：["h","a","n","n","a","H"]
 

提示：
1 <= s.length <= 105
s[i] 都是 ASCII 码表中的可打印字符

来源：力扣（LeetCode）
链接：https://leetcode.cn/problems/reverse-string

[Carlos Wei (Haochen)]

问题分析

遍历字符串，头和尾巴进行互换即可：

static int32_t reverse_str(char *str)
{
    int32_t ret = 0;
    size_t len = 0;
    size_t i = 0;

    UTILS_CHECK_PTR(str);
    UTILS_CHECK_LEN(len = strlen(str));

    for (i = 0; i < len / 2; i ++) {
        utils_swap_char(&(str[i]), &(str[len - i - 1]));
    }

finish:
    return ret;
}

[Carlos Wei (Haochen)]

code:

https://github.com/carloscn/structstudy/blob/master/c_programming/str/17_reverse-string_344.c

result: