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How to Solve Number of Unique Subjects Taught by Each Teacher Problem
Master the Number of Unique Subjects Taught by Each Teacher LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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LeetCode ProblemNumber of Unique Subjects Taught by Each Teacher
Table: Teacher Write a solution to calculate the number of unique subjects each teacher teaches in the university. Return the result table in any order. The result format is shown in the following example.
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Problem Breakdown
Understanding the Number of Unique Subjects Taught by Each Teacher Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
Table: Teacher Write a solution to calculate the number of unique subjects each teacher teaches in the university. Return the result table in any order. The result format is shown in the following example.
EasyProblem #2356
LeetCodeNumber of Unique Subjects Taught by Each Teacher
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Database
How Phantom Code Helps
Get real-time assistance for Number of Unique Subjects Taught by Each Teacher problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
—
Output
—
# Example 2
Input
Teacher table: +------------+------------+---------+ | teacher_id | subject_id | dept_id | +------------+------------+---------+ | 1 | 2 | 3 | | 1 | 2 | 4 | | 1 | 3 | 3 | | 2 | 1 | 1 | | 2 | 2 | 1 | | 2 | 3 | 1 | | 2 | 4 | 1 | +------------+------------+---------+
Output
+------------+-----+ | teacher_id | cnt | +------------+-----+ | 1 | 2 | | 2 | 4 | +------------+-----+
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Solve Number of Unique Subjects Taught by Each Teacher — Table: Teacher Write a solution to calculate the number of unique subjects each ...
Here's the optimal approach using Database:
def solve(input):
# Optimal O(n) solution
return result
Time: O(n) | Space: O(n)
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Frequently Asked Questions
Common questions about solving Number of Unique Subjects Taught by Each Teacher and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Number of Unique Subjects Taught by Each Teacher 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 Unique Subjects Taught by Each Teacher?
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 Unique Subjects Taught by Each Teacher?
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 Unique Subjects Taught by Each Teacher 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 Unique Subjects Taught by Each Teacher 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 Unique Subjects Taught by Each Teacher 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 Unique Subjects Taught by Each Teacher 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 Unique Subjects Taught by Each Teacher 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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