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80 lines
2.9 KiB
80 lines
2.9 KiB
6 years ago
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---
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id: geometry
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3 years ago
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title: Geometry cheatsheet for coding interviews
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description: Geometry study guide for coding interviews, including practice questions, techniques, time complexity, and recommended resources
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keywords:
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[
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geometry coding interview study guide,
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geometry tips for coding interviews,
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geometry practice questions,
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geometry useful techniques,
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geometry time complexity,
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geometry recommended study resources,
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]
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sidebar_label: Geometry
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3 years ago
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toc_max_heading_level: 2
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6 years ago
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---
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7 years ago
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3 years ago
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<head>
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<meta property="og:image" content="https://www.techinterviewhandbook.org/social/algorithms/algorithms/algorithms-geometry.png" />
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</head>
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3 years ago
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## Introduction
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6 years ago
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3 years ago
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Geometry is a branch of mathematics that is concerned with properties of space that are related with distance, shape, size, and relative position of figures. Advanced geometry (e.g. 3D geometry) is not taught in most Computer Science courses, so you can expect that you will only be asked on 2D geometry.
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In algorithm interviews, geometry is usually not be the focus of the problem (you're not being evaluated on mathematics after all). You typically have to use other algorithms and/or data structures in the problem.
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## Corner cases
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- Zero values. This always gets people.
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## Techniques
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### Distance between two points
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When comparing the between two points, using dx<sup>2</sup> + dy<sup>2</sup> is sufficient. It is unnecessary to square root the value. Examples: [K Closest Points to Origin](https://leetcode.com/problems/k-closest-points-to-origin/)
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### Overlapping circles
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6 years ago
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To find out if two circles overlap, check that the distance between the two centers of the circles is less than the sum of their radii.
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3 years ago
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### Overlapping rectangles
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Two rectangles overlap if the following is true:
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```py
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overlap = rect_a.left < rect_b.right and \
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rect_a.right > rect_b.left and \
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rect_a.top > rect_b.bottom and \
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rect_a.bottom < rect_b.top
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```
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Here's a [nice visualization](https://silentmatt.com/rectangle-intersection/). Examples: [Rectangle Overlap](https://leetcode.com/problems/rectangle-overlap/)
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5 years ago
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## Sample questions
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6 years ago
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7 years ago
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- You have a plane with lots of rectangles on it, find out how many of them intersect.
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- Which data structure would you use to query the k-nearest points of a set on a 2D plane?
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- Given many points, find k points that are closest to the origin.
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- How would you triangulate a polygon?
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3 years ago
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3 years ago
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## Essential questions
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_These are essential questions to practice if you're studying for this topic._
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3 years ago
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- [Rectangle Overlap](https://leetcode.com/problems/rectangle-overlap/)
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3 years ago
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## Recommended practice questions
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_These are recommended questions to practice after you have studied for the topic and have practiced the essential questions._
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3 years ago
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- [K Closest Points to Origin](https://leetcode.com/problems/k-closest-points-to-origin/)
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- [Rectangle Area](https://leetcode.com/problems/rectangle-area/)
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3 years ago
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## Recommended courses
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import AlgorithmCourses from '../\_courses/AlgorithmCourses.md'
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<AlgorithmCourses />
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