Oct 22

Author: siddydutta

2024-10-October-LeetCoding-Challenge/Kth Largest Sum in a Binary Tree.py

@@ -0,0 +1,53 @@
+from collections import deque
+from heapq import heappop, heappush
+from typing import Optional
+
+
+# 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 kthLargestLevelSum(self, root: Optional[TreeNode], k: int) -> int:
+        heap = []
+        queue = deque([root])
+        while queue:
+            level_sum = 0
+            next_level = []
+            while queue:
+                node = queue.popleft()
+                level_sum += node.val
+                next_level.extend(filter(None, (node.left, node.right)))
+            heappush(heap, level_sum)
+            if len(heap) > k:
+                heappop(heap)
+            queue = deque(next_level)
+        return heap[0] if len(heap) == k else -1
+
+
+def main():
+    root = TreeNode(5)
+    root.left = TreeNode(8)
+    root.right = TreeNode(9)
+    root.left.left = TreeNode(2)
+    root.left.right = TreeNode(1)
+    root.right.left = TreeNode(3)
+    root.right.right = TreeNode(7)
+    root.left.left.left = TreeNode(4)
+    root.left.left.right = TreeNode(6)
+    k = 2
+    assert Solution().kthLargestLevelSum(root, k) == 13
+
+    root = TreeNode(1)
+    root.left = TreeNode(2)
+    root.left.left = TreeNode(3)
+    k = 1
+    assert Solution().kthLargestLevelSum(root, k) == 3
+
+
+if __name__ == '__main__':
+    main()

2024-10-October-LeetCoding-Challenge/README.md

@@ -24,7 +24,7 @@
 | October 19 | [1545. Find Kth Bit in Nth Binary String](https://leetcode.com/problems/find-kth-bit-in-nth-binary-string/) | Medium | Unsolved |
 | October 20 | [1106. Parsing A Boolean Expression](https://leetcode.com/problems/parsing-a-boolean-expression/) | Hard | Solved |
 | October 21 | [1593. Split a String Into the Max Number of Unique Substrings](https://leetcode.com/problems/split-a-string-into-the-max-number-of-unique-substrings/) | Medium | Solved |
-| October 22 | []() |  |  |
+| October 22 | [2583. Kth Largest Sum in a Binary Tree](https://leetcode.com/problems/kth-largest-sum-in-a-binary-tree/) | Medium | Solved |
 | October 23 | []() |  |  |
 | October 24 | []() |  |  |
 | October 25 | []() |  |  |
@@ -40,5 +40,5 @@
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 2 | 2 | 0 |
-| Medium | 17 | 9 | 8 |
+| Medium | 18 | 10 | 8 |
 | Hard   | 2 | 1 | 1 |