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?

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class Solution:
    def sortedSquares(self, nums: List[int]) -> List[int]:
        n = len(nums)
        result = [0] * n
        left = 0
        right = n - 1
        
        for i in range(n):
            if abs(nums[left]) < abs(nums[right]):
                num = nums[right]
                right -= 1
            else:
                num = nums[left]
                left += 1
            result[n-i-1] = num * num
        
        return result