Given the root of a binary tree, return an array of the largest value in each row of the tree (0-indexed).
Example 1:
Input: root = [1,3,2,5,3,null,9]
Output: [1,3,9]
Example 2:
Input: root = [1,2,3]
Output: [1,3]
Constraints:
- The number of nodes in the tree will be in the range
[0, 104]. -
-231 <= Node.val <= 231 - 1
SOLUTION:
# 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]:
mvals = {}
nodes = [(root, 0)]
mlevel = -1
while len(nodes) > 0:
curr, l = nodes.pop()
if curr:
mlevel = max(mlevel, l)
mvals[l] = max(mvals.get(l, float('-inf')), curr.val)
nodes.append((curr.left, l + 1))
nodes.append((curr.right, l + 1))
return [mvals[l] for l in range(mlevel + 1)]
Top comments (0)