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#2460 - Apply Operations to an Array

Problem Description

You are given a 0-indexed array nums of size n consisting of non-negative integers.

You need to apply n - 1 operations to this array where, in the ith operation (0-indexed), you will apply the following on the ith element of nums:

  • If nums[i] == nums[i + 1], then multiply nums[i] by 2 and set nums[i + 1] to 0. Otherwise, you skip this operation.

After performing all the operations, shift all the 0's to the end of the array.

  • For example, the array [1,0,2,0,0,1] after shifting all its 0's to the end, is [1,2,1,0,0,0].

Return the resulting array.

Note that the operations are applied sequentially, not all at once.

Solution

/**
 * @param {number[]} nums
 * @return {number[]}
 */
var applyOperations = function(nums) {
  for (let i = 0; i < nums.length - 1; i++) {
    if (nums[i] === nums[i + 1]) {
      nums[i] *= 2;
      nums[i + 1] = 0;
    }
  }
  return [...nums.filter(n => n), ...nums.filter(n => !n)];
};