344. Reverse String
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
题意来讲就是在字符数组中原地前后交换，这里我也采用了异或来做。
但是严格来讲，在这里用异或是错误的。在工程中不允许出现这样的代码。
推荐一篇文章：用异或来交换两个变量是错误的
- 时间复杂度 O(N)
- 空间复杂度 O(1)
代码
impl Solution { pub fn reverse_string(s: &mut Vec<char>) { let n = s.len(); if n == 0 { return; } for i in 0..n/2 { let j = n -1 -i; s[i] = ((s[i] as u8) ^ (s[j] as u8)) as char; s[j] = ((s[i] as u8) ^ (s[j] as u8)) as char; s[i] = ((s[i] as u8) ^ (s[j] as u8)) as char; } } } |
- 执行用时: 28 ms
- 内存消耗: 5.3 MB
题型与相似题
题型
1.字符串
2.双指针
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