344. Reverse String

Posted on Edited on In

344. Reverse String

Description

Difficulty: Easy

Related Topics: Two Pointers, String

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 1:

1
2
Input: s = ["h","e","l","l","o"]
Output: ["o","l","l","e","h"]

Example 2:

1
2
Input: s = ["H","a","n","n","a","h"]
Output: ["h","a","n","n","a","H"]

Constraints:

Hints/Notes

  • N/A

Solution

Language: C++

1
2
3
4
5
6
7
8
9
10
11
12
13
class Solution {
public:
    void reverseString(vector<char>& s) {
        int left = 0, right = s.size() - 1;
        while (left < right) {
            char c = s[right];
            s[right] = s[left];
            s[left] = c;
            left++;
            right--;
        }
    }
};