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How to Solve Number of Nodes in the Sub-Tree With the Same Label Problem
Master the Number of Nodes in the Sub-Tree With the Same Label LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#1519
LeetCode ProblemNumber of Nodes in the Sub-Tree With the Same Label
You are given a tree (i.e. a connected, undirected graph that has no cycles) consisting of n nodes numbered from 0 to n - 1 and exactly n - 1 edges. The root of the tree is the node 0, and each node of the tree has a label which is a lower-case character given in the string labels (i.e. The node with the number i has the label labels[i]). The edges array is given on the form edges[i] = [ai, bi], which means there is an edge between nodes ai and bi in the tree. Return an array of size n where ans[i] is the number of nodes in the subtree of the ith node which have the same label as node i. A subtree of a tree T is the tree consisting of a node in T and all of its descendant nodes.
Hash TableTreeDepth-First SearchBreadth-First SearchCounting
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Problem Breakdown
Understanding the Number of Nodes in the Sub-Tree With the Same Label Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
You are given a tree (i.e. a connected, undirected graph that has no cycles) consisting of n nodes numbered from 0 to n - 1 and exactly n - 1 edges. The root of the tree is the node 0, and each node of the tree has a label which is a lower-case character given in the string labels (i.e. The node with the number i has the label labels[i]). The edges array is given on the form edges[i] = [ai, bi], which means there is an edge between nodes ai and bi in the tree. Return an array of size n where ans[i] is the number of nodes in the subtree of the ith node which have the same label as node i. A subtree of a tree T is the tree consisting of a node in T and all of its descendant nodes.
MediumProblem #1519
LeetCodeNumber of Nodes in the Sub-Tree With the Same Label
Related Topics
Hash TableTreeDepth-First SearchBreadth-First SearchCounting
How Phantom Code Helps
Get real-time assistance for Number of Nodes in the Sub-Tree With the Same Label problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
n = 7, edges = [[0,1],[0,2],[1,4],[1,5],[2,3],[2,6]], labels = "abaedcd"
Output
[2,1,1,1,1,1,1]
# Example 2
Input
n = 4, edges = [[0,1],[1,2],[0,3]], labels = "bbbb"
Output
[4,2,1,1]
# Example 3
Input
n = 5, edges = [[0,1],[0,2],[1,3],[0,4]], labels = "aabab"
Output
[3,2,1,1,1]
Constraints
1 <= n <= 105
edges.length == n - 1
edges[i].length == 2
0 <= ai, bi < n
ai != bi
labels.length == n
labels is consisting of only of lowercase English letters.
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Frequently Asked Questions
Common questions about solving Number of Nodes in the Sub-Tree With the Same Label and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Number of Nodes in the Sub-Tree With the Same Label during interviews?
Phantom Code generates complete solutions instantly with proper complexity analysis, letting you focus on explaining your approach and demonstrating problem-solving skills rather than getting stuck on implementation details during high-pressure situations.
What if the interviewer asks follow-up questions or modifications to problems like Number of Nodes in the Sub-Tree With the Same Label?
Phantom Code adapts in real-time. Screenshot the modified problem or use audio mode to capture the interviewer's follow-up, and get an updated solution within seconds — including edge cases and optimizations.
Can Phantom Code help me communicate my solution for problems like Number of Nodes in the Sub-Tree With the Same Label?
Yes. Phantom Code provides step-by-step approach explanations with 3 progressive thoughts, so you can walk through your solution naturally. It also provides time and space complexity analysis to discuss trade-offs.
How does Phantom Code assist with different programming languages for Number of Nodes in the Sub-Tree With the Same Label type problems?
Phantom Code supports 11 programming languages including Python, Java, C++, JavaScript, TypeScript, Go, Rust, Ruby, Swift, Kotlin, and C#. Set your preferred language and get idiomatic solutions.
What coding mistakes does Phantom Code help me avoid during Number of Nodes in the Sub-Tree With the Same Label interviews?
Phantom Code catches common mistakes like off-by-one errors, missing edge cases, incorrect base conditions, and suboptimal approaches. It provides clean, well-structured code that handles all edge cases.
Is Phantom Code detectable when solving problems like Number of Nodes in the Sub-Tree With the Same Label during live interviews?
No. Phantom Code runs as an invisible desktop overlay that doesn't appear in screen shares, recordings, or proctoring software. It works with Zoom, HackerRank, CodeSignal, CoderPad, and all major platforms.
How does Phantom Code help when I'm struggling with Number of Nodes in the Sub-Tree With the Same Label style questions under pressure?
The AI provides structured guidance: first the approach (what algorithm/data structure to use and why), then the implementation with clean code, and finally complexity analysis. This helps you think clearly even under pressure.
Does Phantom Code work for the coding platforms used in Number of Nodes in the Sub-Tree With the Same Label interviews?
Yes. Phantom Code works with all major coding platforms including LeetCode, HackerRank, CodeSignal, CoderPad, HackerEarth, and any browser-based coding environment.
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