Leetcode 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:

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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:

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

Note: It’s very easy to come up with a brute force way. But double pointers is fancier.

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/**
* @param {number[]} nums
* @return {number[]}
*/

/* Brute force */
var sortedSquares = function (nums) {
const arr = nums.map((e) => e ** 2);
return arr.sort((a, b) => a - b);
};

/* Double pointers */
var sortedSquares = function(nums) {
let ans = [];
// sort it first for later use.
nums.sort((a,b) => (a - b));
let start = 0, end = nums.length - 1;
for (let i = nums.length - 1; i >= 0; i--) {
if (nums[start]**2 > nums[end]**2) {
ans[i] = nums[start++]**2;
} else {
ans[i] = nums[end--]**2;
}
}
return ans;
};