Reverse String

Introduction

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

Very simple and standard solution could be like this:

func reverseString(s []byte)  {
    n := len(s)
    for i, j := 0, n-1; i < j; i, j = i+1, j-1 {
        s[i], s[j] = s[j], s[i]
    }
}

Performance of this solution is:

Runtime: 40 ms
Memory Usage: 6.3 MB