D. J.:

- Added the leetcode problem and solution for 102 and 103
- Fixed typing errors

Author: nobodyPerfecZ

README.md

@@ -0,0 +1,30 @@
+from typing import List, Optional
+
+from awesome_python_leetcode.tree import TreeNode
+
+
+class Solution:
+    """Base class for all LeetCode Problems."""
+
+    def levelOrder(self, root: Optional[TreeNode]) -> List[List[int]]:
+        """
+        Given the root of a binary tree, return the level order traversal of its nodes'
+        values. (i.e., from left to right, level by level).
+        """
+        if root is None:
+            return []
+        parents = [root]
+        result = []
+        while parents:
+            # Build childs and level
+            childs = []
+            level = []
+            for p in parents:
+                if p.left:
+                    childs.append(p.left)
+                if p.right:
+                    childs.append(p.right)
+                level.append(p.val)
+            parents = childs
+            result.append(level)
+        return result

awesome_python_leetcode/_102_binary_tree_level_order_traversal.py

@@ -0,0 +1,39 @@
+from typing import List, Optional
+
+from awesome_python_leetcode.tree import TreeNode
+
+
+class Solution:
+    """Base class for all LeetCode Problems."""
+
+    def zigzagLevelOrder(self, root: Optional[TreeNode]) -> List[List[int]]:
+        """
+        Given the root of a binary tree, return the zigzag level order traversal of its
+        nodes' values. (i.e., from left to right, then right to left for the next level
+        and alternate between).
+        """
+        if root is None:
+            return []
+        parents = [root]
+        result = []
+        even_level = True
+        while parents:
+            # Build childs and zig-zag levelorder
+            childs = []
+            levelorder = []
+            for p in reversed(parents):
+                if even_level:
+                    if p.left:
+                        childs.append(p.left)
+                    if p.right:
+                        childs.append(p.right)
+                else:
+                    if p.right:
+                        childs.append(p.right)
+                    if p.left:
+                        childs.append(p.left)
+                levelorder.append(p.val)
+            parents = childs
+            result.append(levelorder)
+            even_level = not even_level
+        return result

awesome_python_leetcode/_103_binary_tree_zigzag_level_order_traversal.py

@@ -2,6 +2,8 @@
 
 
 class Solution:
+    """Base class for all LeetCode Problems."""
+
     def singleNumber(self, nums: List[int]) -> int:
         """
         Given a non-empty array of integers nums, every element appears twice except for

awesome_python_leetcode/_136_single_number.py

@@ -2,6 +2,8 @@
 
 
 class Solution:
+    """Base class for all LeetCode Problems."""
+
     def singleNumber(self, nums: List[int]) -> int:
         """
         Given an integer array nums where every element appears three times except for

awesome_python_leetcode/_137_single_number_II.py

@@ -1,4 +1,6 @@
 class Solution:
+    """Base class for all LeetCode Problems."""
+
     def reverseBits(self, n: int) -> int:
         """Reverse bits of a given 32 bits unsigned integer."""
         res = 0

awesome_python_leetcode/_190_reverse_bits.py

@@ -1,4 +1,6 @@
 class Solution:
+    """Base class for all LeetCode Problems."""
+
     def hammingWeight(self, n: int) -> int:
         """
         Given a positive integer n, write a function that returns the number of set bits

awesome_python_leetcode/_191_number_of_1_bits.py

@@ -4,6 +4,8 @@
 
 
 class Solution:
+    """Base class for all LeetCode Problems."""
+
     def rightSideView(self, root: Optional[TreeNode]) -> List[int]:
         """
         Given the root of a binary tree, imagine yourself standing on the right side of

awesome_python_leetcode/_199_binary_tree_right_side_view.py

@@ -1,4 +1,6 @@
 class Solution:
+    """Base class for all LeetCode Problems."""
+
     def rangeBitwiseAnd(self, left: int, right: int) -> int:
         """
         Given two integers left and right that represent the range [left, right],

awesome_python_leetcode/_201_bitwise_and_of_numbers_range.py

@@ -4,6 +4,8 @@
 
 
 class Solution:
+    """Base class for all LeetCode Problems."""
+
     def averageOfLevels(self, root: Optional[TreeNode]) -> List[float]:
         """
         Given the root of a binary tree, return the average value of the nodes on each