Intermediate C++ Game Programming Tutorial 24
From Chilipedia
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.