344. Reverse String.cpp

// 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.
// Accepted
// 2,559,286
// Submissions
// 3,276,894


class Solution {
public:
    void reverseString(vector<char>& s) {
        int start = 0;
        int end = s.size()-1;
        while(start<end){
            int temp = s[start];
            s[start]=s[end];
            s[end]=temp;
            start++;
            end--;
        }
    }
};