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 <= 104
• -104 <= nums[i] <= 104
• nums is sorted in non-decreasing order.

 

Follow up: Squaring each element and sorting the new array is very trivial, could you find an O(n) solution using a different approach?

In JS:

var sortedSquares = function(nums) {

    let arr = [];

    for(let i=0; i<nums.length; i++){

      let sqrt = nums[i] * nums[i];

      arr.push(sqrt);

    }

     arr.sort(function(a, b){return a - b});

     return arr;

};