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?SOLUTION:

class Solution:
    def sortedSquares(self, nums: List[int]) -> List[int]:
        n = len(nums)
        beg = 0
        end = n - 1
        while beg <= end:
            mid = (beg + end) // 2
            if nums[mid] > 0 and nums[mid - 1] < 0:
                beg = mid
                break
            elif beg == end:
                break
            elif nums[mid] < 0:
                beg = mid + 1
            else:
                end = mid
        op = []
        i = beg - 1
        j = beg
        while i >= 0 and j <= n - 1:
            if nums[i] * nums[i] < nums[j] * nums[j]:
                op.append(nums[i] * nums[i])
                i -= 1
            else:
                op.append(nums[j] * nums[j])
                j += 1
        while i >= 0:
            op.append(nums[i] * nums[i])
            i -= 1
        while j <= n - 1:
            op.append(nums[j] * nums[j])
            j += 1
        return op