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

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(Video Timestamp Index)
(Video Timestamp Index)
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** <code>map.insert( {key,value} )</code> to insert (key,value) pairs
 
** <code>map.insert( {key,value} )</code> to insert (key,value) pairs
 
** <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
 
+
* <code>std::map</code> does lookup in O(log(n)), it uses a binary tree implementation [https://youtu.be/JlPsCoCO99o?t=2m46s 2:46]
  
 
[https://youtu.be/LsjFAx-dG5I Tutorial 24.2]
 
[https://youtu.be/LsjFAx-dG5I Tutorial 24.2]

Revision as of 00:32, 8 December 2019

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

  • 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

  • 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 std::map<KeyType,ValueType> class 0:46
    • Maps consist of keys to lookup (associated with) values
    • map.insert( {key,value} ) to insert (key,value) pairs
    • map[key] returns a reference to the ValueType for a KeyType
  • std::map does lookup in O(log(n)), it uses a binary tree implementation 2:46

Tutorial 24.2

  • [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