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

Question

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?

Python Solution

class Solution:
    def sortedSquares(self, A: List[int]) -> List[int]:
        
        answer = [0] * len(A)
        l, r = 0, len(A) - 1
        while l <= r:
            left, right = abs(A[l]), abs(A[r])
            if left > right:
                answer[r - l] = left * left
                l += 1
            else:
                answer[r - l] = right * right
                r -= 1
        return( answer)