Dec 25

Author: siddydutta

2024-12-December-LeetCoding-Challenge/Find Largest Value in Each Tree Row.py

@@ -0,0 +1,44 @@
+from collections import deque
+from typing import List, 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 largestValues(self, root: Optional[TreeNode]) -> List[int]:
+        result = []
+        level = deque([root] if root else [])
+        while level:
+            max_val = float('-inf')
+            n_level = len(level)
+            for _ in range(n_level):
+                node = level.popleft()
+                max_val = max(max_val, node.val)
+                level.extend(filter(None, (node.left, node.right)))
+            result.append(max_val)
+        return result
+
+
+def main():
+    root = TreeNode(1)
+    root.left = TreeNode(3)
+    root.right = TreeNode(2)
+    root.left.left = TreeNode(5)
+    root.left.right = TreeNode(3)
+    root.right.right = TreeNode(9)
+    assert Solution().largestValues(root) == [1, 3, 9]
+
+    root = TreeNode(1)
+    root.left = TreeNode(2)
+    root.right = TreeNode(3)
+    assert Solution().largestValues(root) == [1, 3]
+
+
+if __name__ == '__main__':
+    main()

2024-12-December-LeetCoding-Challenge/README.md

@@ -27,7 +27,7 @@
 | December 22 | [2940. Find Building Where Alice and Bob Can Meet](https://leetcode.com/problems/find-building-where-alice-and-bob-can-meet/) | Hard | Unsolved |
 | December 23 | [2471. Minimum Number of Operations to Sort a Binary Tree by Level](https://leetcode.com/problems/minimum-number-of-operations-to-sort-a-binary-tree-by-level/) | Medium | Solved |
 | December 24 | [3203. Find Minimum Diameter After Merging Two Trees](https://leetcode.com/problems/find-minimum-diameter-after-merging-two-trees/) | Hard | Unsolved |
-| December 25 | []() |  |  |
+| December 25 | [515. Find Largest Value in Each Tree Row](https://leetcode.com/problems/find-largest-value-in-each-tree-row/) | Medium | Solved |
 | December 26 | []() |  |  |
 | December 27 | []() |  |  |
 | December 28 | []() |  |  |
@@ -39,5 +39,5 @@
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 5 | 5 | 0 |
-| Medium | 16 | 10 | 6 |
+| Medium | 17 | 11 | 6 |
 | Hard   | 3 | 0 | 3 |