977. Squares of a Sorted Array

Given an integer array nums sorted in non-decreasing order, return an array of the squares of each number sorted in non-decreasing order

Example 1:

• Input: nums = [-4,-1,0,3,10]
• Output: [0,1,9,16,100]
• Explanation: After squaring, the array becomes [16,1,0,9,100]. After sorting, it becomes [0,1,9,16,100].

Example 2:

• Input: nums = [-7,-3,2,3,11]
• Output: [4,9,9,49,121]

Constraints:

• 1 <= nums.length <= 10^4
• -10^4 <= nums[i] <= 10^4
• nums is sorted in non-decreasing order.

Approach

Solution

/**
 * @param {number[]} nums
 * @return {number[]}
 */
var sortedSquares = function(nums) {
  let n = nums.length;
  let ans = new Array(nums.length);
  let left = 0, right = nums.length - 1;

  for (let i = n -1; i >= 0; i--){
    let square;
    if(Math.abs(nums[left]) < Math.abs(nums[right])){
      square = nums[right];
      right--;
    }else{
      square = nums[left];
      left++;
    }
    ans[i] = square*square;
  }
  return ans;
};

Explanation