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How to Solve Course Schedule IV Problem
Master the Course Schedule IV LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#1462
LeetCode ProblemCourse Schedule IV
There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [ai, bi] indicates that you must take course ai first if you want to take course bi. Prerequisites can also be indirect. If course a is a prerequisite of course b, and course b is a prerequisite of course c, then course a is a prerequisite of course c. You are also given an array queries where queries[j] = [uj, vj]. For the jth query, you should answer whether course uj is a prerequisite of course vj or not. Return a boolean array answer, where answer[j] is the answer to the jth query.
Depth-First SearchBreadth-First SearchGraphTopological Sort
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Problem Breakdown
Understanding the Course Schedule IV Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [ai, bi] indicates that you must take course ai first if you want to take course bi. Prerequisites can also be indirect. If course a is a prerequisite of course b, and course b is a prerequisite of course c, then course a is a prerequisite of course c. You are also given an array queries where queries[j] = [uj, vj]. For the jth query, you should answer whether course uj is a prerequisite of course vj or not. Return a boolean array answer, where answer[j] is the answer to the jth query.
MediumProblem #1462
LeetCodeCourse Schedule IV
Related Topics
Depth-First SearchBreadth-First SearchGraphTopological Sort
How Phantom Code Helps
Get real-time assistance for Course Schedule IV problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
numCourses = 2, prerequisites = [[1,0]], queries = [[0,1],[1,0]]
Output
[false,true]
# Example 2
Input
numCourses = 2, prerequisites = [], queries = [[1,0],[0,1]]
Output
[false,false]
# Example 3
Input
numCourses = 3, prerequisites = [[1,2],[1,0],[2,0]], queries = [[1,0],[1,2]]
Output
[true,true]
Constraints
2 <= numCourses <= 100
0 <= prerequisites.length <= (numCourses * (numCourses - 1) / 2)
prerequisites[i].length == 2
0 <= ai, bi <= numCourses - 1
ai != bi
All the pairs [ai, bi] are unique.
The prerequisites graph has no cycles.
1 <= queries.length <= 104
0 <= ui, vi <= numCourses - 1
ui != vi
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Solve Course Schedule IV — There are a total of numCourses courses you have to take, labeled from 0 to numC...
Here's the optimal approach using Depth-First Search:
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 Course Schedule IV and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Course Schedule IV 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 Course Schedule IV?
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 Course Schedule IV?
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 Course Schedule IV 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 Course Schedule IV 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 Course Schedule IV 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 Course Schedule IV 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 Course Schedule IV 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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