[parkhojeong] WEEK 14 Solutions (#2870)

* counting-bits solution

* binary-tree-level-order-traversal solution

* house-robber-ii solution

* counting-bits solution

* house-robber-ii solution

* binary-tree-level-order-traversal solution

Author: parkhojeong

binary-tree-level-order-traversal/parkhojeong.py

@@ -0,0 +1,28 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution:
+    def levelOrder(self, root: TreeNode | None) -> list[list[int]]:
+        if root is None:
+            return []
+
+        deq = deque([root])
+
+        output = []
+        while deq:
+            nodes = []
+
+            for _ in range(len(deq)):
+                node = deq.popleft()
+                nodes.append(node.val)
+                if node.left:
+                    deq.append(node.left)
+                if node.right:
+                    deq.append(node.right)
+
+            output.append(nodes)
+
+        return output

counting-bits/parkhojeong.py

@@ -0,0 +1,13 @@
+class Solution:
+    def countBits(self, n: int) -> list[int]:
+        if n == 0:
+            return [0]
+
+        arr = [0, 1]
+        def count(n: int) -> int:
+            return arr[n // 2] + n % 2
+
+        for i in range(2, n + 1):
+            arr.append(count(i))
+
+        return arr

house-robber-ii/parkhojeong.py

@@ -0,0 +1,21 @@
+class Solution:
+    def rob(self, nums: list[int]) -> int:
+        if len(nums) == 1:
+            return nums[0]
+
+        return max(
+            max(self.rob_linear(nums[:-1])),
+            max(self.rob_linear(nums[1:] ))
+        )
+
+    def rob_linear(self, nums: list[int]):
+        N = len(nums)
+
+        dp = [0] * (N + 1)
+        dp[1] = nums[0]
+
+        for i in range(2, N + 1):
+            dp[i] = max(dp[i - 2] + nums[i - 1], dp[i - 1])
+
+
+        return dp