Count Nodes With the Highest Score — LeetCode 2049 Python Solution
MediumTreeDepth-First SearchArrayBinary Tree
- Problem
- #2049
- Pattern
- Tree Traversal
- Reading time
- 5 min
- Source
- leetcode.com
The problem
There is a binary tree rooted at 0 consisting of n nodes. The nodes are labeled from 0 to n - 1.
Example
- Input
- parents = [-1,2,0,2,0]
- Output
- 3
- Explanation
- - The score of node 0 is: 3 * 1 = 3
Python solution
Python
class Solution:
def countHighestScoreNodes(self, parents: List[int]) -> int:
def dfs(i: int, fa: int):
cnt = score = 1
for j in g[i]:
if j != fa:
t = dfs(j, i)
score *= t
cnt += t
if n - cnt:
score *= n - cnt
nonlocal ans, mx
if mx < score:
mx = score
ans = 1
elif mx == score:
ans += 1
return cnt
n = len(parents)
g = [[] for _ in range(n)]
for i in range(1, n):
g[parents[i]].append(i)
ans = mx = 0
dfs(0, -1)
return ansComplexity
| Measure | Complexity |
|---|---|
| Time | O(n) |
| Space | O(n) auxiliary |
Pattern: Tree Traversal
Choose the order — preorder, inorder, postorder, level — and the problem solves itself. LeetCode 2049. Count Nodes With the Highest Score is filed here because LeetCode tags it Tree and Binary Tree, which is the vocabulary this hub collects.
The tree traversal guide has the Python template for the pattern and the 225 LeetCode problems that use it.
Related problems
Frequently asked questions
- How hard is LeetCode 2049. Count Nodes With the Highest Score?
- LeetCode 2049. Count Nodes With the Highest Score is rated Medium on LeetCode.
- What is the time complexity of LeetCode 2049. Count Nodes With the Highest Score?
- The Python solution on this page runs in O(n).
- What is the space complexity of LeetCode 2049. Count Nodes With the Highest Score?
- The Python solution on this page uses O(n) auxiliary space.
- What topics does LeetCode 2049. Count Nodes With the Highest Score cover?
- LeetCode 2049. Count Nodes With the Highest Score is tagged Tree, Depth-First Search, Array and Binary Tree on LeetCode.