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Squares of a Sorted Array

Problem Statement​

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

Leetcode link

Examples​

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.

Code​

Python3 Code
class Solution:
    def sortedSquares(self, nums: List[int]) -> List[int]:
        res = []
        num_deque = collections.deque(nums)

        while num_deque:
            left = num_deque[0] ** 2
            right = num_deque[-1] ** 2

            if left > right:
                res.append(left)
                num_deque.popleft()
            else:
                res.append(right)
                num_deque.pop()

        return res[::-1]