Reverse Array

Problem Statement

Given an array of integers, reverse it in-place and return the modified array.

Function Signature:

function reverseArray(arr) {
  // Your code here
}

Examples

Input	Output	Explanation
[1, 2, 3, 4, 5]	[5, 4, 3, 2, 1]	Elements are reversed
[1, 2]	[2, 1]	Two elements swap positions
[42]	[42]	Single element stays the same

Constraints

• Array length: 0 ≤ arr.length ≤ 10,000
• Element values: -10⁹ ≤ arr[i] ≤ 10⁹

Interactive Editor

function reverseArray(arr) {
// Your code here

}

Tests: 5 total

Hints

Hint 1: Two Pointers

Use two pointers starting at opposite ends of the array. Swap the elements they point to, then move them toward each other.

Solution

View Solution Explanation

function reverseArray(arr) {
  let left = 0;
  let right = arr.length - 1;

  while (left < right) {
    const temp = arr[left];
    arr[left] = arr[right];
    arr[right] = temp;
    left++;
    right--;
  }

  return arr;
}

Swap elements at left and right pointers, then move them inward until they meet.

Complexity: O(n) time, O(1) space.