right-rotate-array-in-javascript.md

Right Rotate Array in JavaScript

📝 Problem

right Rotate Array in JavaScript

📌 Examples

Example 1

Input: array = [1, 2, 3, 4, 5], position = 2
Output: [4, 5, 1, 2, 3]

Example 2

Input: array = ['a', 'b', 'c', 'd'], position = 3
Output: ['b', 'c', 'd', 'a']

Example 3

Input: array = ['b', 'c', 'd', 'a'], position = -4
Output: ❌ Throw error => Shift amount must be non-negative.

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✅ Solutions

💡 Solution 1: rotateArrayRight

function rotateArrayRight(arr, k) {
  if (!Array.isArray(arr)) {
    throw new Error("Input must be an array.");
  }
  if (k < 0) {
    throw new Error("Shift amount must be non-negative.");
  }

  const len = arr.length;
  k = k % len;

  // Handle edge cases efficiently
  if (k === 0 || len === 0) {
    return arr;
  }

  // Use a more optimized approach for larger arrays
  if (len >= 2 * k) {
    const temp = arr.slice(len - k);
    arr.splice(len - k);
    arr.unshift(...temp);
  } else {
    // For smaller arrays, use the existing approach
    arr = arr.slice(-k).concat(arr.slice(0, -k));
  }

  return arr;
}

💡 Solution 2: FunctionalRotateRight:

function functionalRotateRight(arr, k) {
  if (!Array.isArray(arr)) {
    throw new Error("Input must be an array.");
  }
  if (k < 0) {
    throw new Error("Shift amount must be non-negative.");
  }

  return arr.reduce((acc, val, i) => {
    const newIndex = (i + k) % arr.length;
    acc[newIndex] = val;
    return acc;
  }, []);
}

💡 Solution 3: ShiftArrayRight:

function shiftArrayRight(arr, k) {
  if (!Array.isArray(arr)) {
    throw new Error("Input must be an array.");
  }
  if (k < 0) {
    throw new Error("Shift amount must be non-negative.");
  }

  const n = arr.length;
  k %= n;
  for (let i = 0; i < k; i++) {
    const last = arr.pop();
    arr.unshift(last);
  }
  return arr;
}