Leetcode344

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”]

Solution:

#include 
#include 

using namespace std;

class Solution {
public:
    void reverseString(vector& s) {

        int i = 0, j = s.size()-1;
        while ( i < j ){
            swap( s[i], s[j]);
            i++;
            j--;
        }

    }
};