#344 Reverse 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:

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

Example 2:

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

Constraints:

• 1 <= s.length <= 105
• s[i] is a printable ascii character.

Solution :

void reverseString(vector<char>& s) {
        int j=s.size()-1;
		int mid = j/2;
		for(int i=0; i<=mid; i++, j--)
		{
			swap(s[i],s[j]);
		}
    }

Complete code:

// function that reverses a string
#include <bits/stdc++.h>
using namespace std;

void reverseString(vector<char>& s) {
		int j=s.size()-1;
		int mid = j/2;
		for(int i=0; i<=mid; i++, j--)
		{
			swap(s[i],s[j]);
		}
		
		for(int i=0; i< s.size(); i++)
			cout << s.at(i) << " ";
		cout << endl;
    }

int main()
{
	vector<char> str = {'a','b','c','d'};
	reverseString(str);
	return 0;
}