Write a function that reverses a string. The input string is given as an array of characters char[] .
Conditions:
Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
Example 1:
Input: ["h","e","l","l","o"]
Output: ["o","l","l","e","h"]
Alogrithm:
- Loop through the half of the array
- swap elements
- profit :-)
Code
/** * @param {character[]} s * @return {void} Do not return anything, modify s in-place instead. */ var reverseString = function(s) { let mid = Math.floor(s.length / 2); for (let i = 0; i < mid; i++) { // Basic Swapping let temp = s[i]; s[i] = s[s.length - i - 1]; s[s.length - i - 1] = temp; } return s }; Alternative Approach
instead of using for loop, you can use pointers
/** * @param {character[]} s * @return {void} Do not return anything, modify s in-place instead. */ var reverseString = function(s) { let left = 0, right = s.length - 1; while (left < right) { let temp = s[right]; s[right--] = s[left]; s[left++] = temp; } return s }; 
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