Difference between revisions of "Intermediate C++ Game Programming Tutorial 24"
From Chilipedia
(→Video Timestamp Index) |
(→Video Timestamp Index) |
||
Line 23: | Line 23: | ||
** <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> | + | * <code>std::map</code> performs lookup in O(log(n)), it uses a Binary tree data structure [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 00:34, 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.
Contents
Topics Covered
Part 1
-
std::map
container interface - Binary tree data structure
-
std::map
key requirements (comparison) -
std::map
gotchas (std::remove_if
andconst
keys) -
std::set
-
std::multimap
andstd::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
overstd::unordered_map
Video Timestamp Index
- 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
performs lookup in O(log(n)), it uses a Binary tree data structure 2:46
- [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.