Difference between revisions of "Intermediate C++ Game Programming Tutorial 24"

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(Video Timestamp Index)
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** <code>map[key]</code> returns a reference to the ValueType for a KeyType
 
** <code>map[key]</code> returns a reference to the ValueType for a KeyType
 
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* A Binary Tree data structure is used to manage the order of maps [https://youtu.be/JlPsCoCO99o?t=2m46s 2:46]
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* A Binary Tree data structure is used to manage the order of map elements [https://youtu.be/JlPsCoCO99o?t=2m46s 2:46]
 
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** <code>std::map</code> performs lookup in O(log(n)), it uses a Binary tree data structure
 
** <code>std::map</code> performs lookup in O(log(n)), it uses a Binary tree data structure

Revision as of 04:54, 20 January 2020

Associative containers are super useful, both as a convenient fast way to create dictionary or mapping for real-world problems like managing game resources, and as a data structure to help solve more abstract algorithmic computer science problems. And hash tables are fast as balls.

Topics Covered

Part 1: ordered associative containers

  • std::map container interface
  • Binary tree data structure
  • std::map key requirements (comparison)
  • std::map gotchas (std::remove_if and const keys)
  • std::set
  • std::multimap and std::multiset

Part 2: unordered associative containers

  • Hash table performance vs. binary tree performance
  • Hash table data structure
  • std::unordered_map key requirements
  • Hash combining
  • std::unordered_map bucket interface and hashing policy
  • When to choose std::map over std::unordered_map

Video Timestamp Index

Tutorial 24.1: The ordered associative containers

[Expand]
  • The std::map<KeyType,ValueType> class 0:46
  • A Binary Tree data structure is used to manage the order of map elements 2:46
  • A look at the std::map cppreference.com documentation: insert, lookup & find 7:35
  • Requirements on KeyType 14:30
  • std::map cppreference.com documentation continued: erase 15:28
  • Two <<important>> things to know when working with associative containers 16:04
  • The std::set<KeyType> class 20:00
  • The std::multimap and std::multiset classes 21:28
  • Practical example of a multimap use case 22:30
  • Lookup in multimaps 25:21

Tutorial 24.2: The unordered associative containers

  • [WORK-IN-PROGRESS]

Homework Assignment

The homework for this video is to enable use of a custom datatype in unordered_map hashing over multiple (4) members of that datatype. The solution video is here.

Supplementary Link

See also