feat(1019-squares-of-a-sorted-array): add py3 solution

1019_squares-of-a-sorted-array/README.md

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+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?

1019_squares-of-a-sorted-array/python3/solution.py

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+class Solution:
+    def sortedSquares(self, nums: List[int]) -> List[int]:
+        left = 0
+        right = i = len(nums) - 1
+        result = [None] * len(nums)
+        
+        while i >= 0:
+            if abs(nums[left]) > abs(nums[right]):
+                result[i] = nums[left] ** 2
+                left += 1
+            else:
+                result[i] = nums[right] ** 2
+                right -= 1
+            
+            i -= 1
+        
+        return result