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How to Solve Count Number of Trapezoids I Problem
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Start Free for WindowsMedium#3623
LeetCode ProblemCount Number of Trapezoids I
You are given a 2D integer array points, where points[i] = [xi, yi] represents the coordinates of the ith point on the Cartesian plane. A horizontal trapezoid is a convex quadrilateral with at least one pair of horizontal sides (i.e. parallel to the x-axis). Two lines are parallel if and only if they have the same slope. Return the number of unique horizontal trapezoids that can be formed by choosing any four distinct points from points. Since the answer may be very large, return it modulo 109 + 7.
ArrayHash TableMathGeometry
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Problem Breakdown
Understanding the Count Number of Trapezoids I Problem
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Problem Statement
You are given a 2D integer array points, where points[i] = [xi, yi] represents the coordinates of the ith point on the Cartesian plane. A horizontal trapezoid is a convex quadrilateral with at least one pair of horizontal sides (i.e. parallel to the x-axis). Two lines are parallel if and only if they have the same slope. Return the number of unique horizontal trapezoids that can be formed by choosing any four distinct points from points. Since the answer may be very large, return it modulo 109 + 7.
MediumProblem #3623
LeetCodeCount Number of Trapezoids I
Related Topics
ArrayHash TableMathGeometry
How Phantom Code Helps
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Examples
# Example 1
Input
points = [[1,0],[2,0],[3,0],[2,2],[3,2]]
Output
3
# Example 2
Input
points = [[0,0],[1,0],[0,1],[2,1]]
Output
1
Constraints
4 <= points.length <= 105
–108 <= xi, yi <= 108
All points are pairwise distinct.
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Solve Count Number of Trapezoids I — You are given a 2D integer array points, where points[i] = [xi, yi] represents t...
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Frequently Asked Questions
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How does Phantom Code help me solve coding problems like Count Number of Trapezoids I 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 Count Number of Trapezoids I?
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 Count Number of Trapezoids I?
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 Count Number of Trapezoids I 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 Count Number of Trapezoids I 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 Count Number of Trapezoids I 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 Count Number of Trapezoids I 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 Count Number of Trapezoids I 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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