Main/Temporary/C++ Data Structures.md

title, created_date, updated_date, aliases, tags

title	created_date	updated_date	aliases	tags
C++ Data Structures	2024-11-11	2024-11-11

C++ Data Structures

Vectors

• stores sequence of data in variable length container (like an array, but variable in size)
• insertions other than at the end are slow, because elements must be shifted
• Applications:
  • Paths and Waypoints and trajectories
  • Vectors of vectors allow to store matrices
  • dynamic resizing
  • any element can be accessed --> random access
  • access all element at once, filter, sort them, etc

Stack and Queues

• storing data in specific order

Stack

• LIFO: Last in first out
  • meaning if i stack 1 then 2 then 3 and then I pop them I get 3 first, then 2 and finally 1
  • 1,2,3 --> 3,2,1
• Applications
  • Backtracking algorithms: if you hit a dead end and you need to go back to a previous node from where you can explore another path.
  • Depth first search
  • Undo/Redo functionality (last action must be undone first)
  • store navigation history (web browsers)
  • manage states (you could go back to a previous state)

Queues

• FIFO: First in First Out
  • 1,2,3 --> 1,2,3
• Applications:
  • Buffers of sensors
  • moving average implementation
  • data streaming

Sets

• collection of unique elements
• you cannot modify elements of a set
• ordered and unordered sets
• Applications
  • UID management:
    • keep track of objects in a scene (label each with a unique id) --> robotics navigation, etc.
  • Store valid configuration sets for system. Invalid configurations can be detected
  • Keep track of visited nodes/cells in grid. unordered cell --> very fast lookup if cell has already been visited
  • Union, intersections and difference
    • used in multi robot systems.
  • Feature and Capabillity Tracking: Keep track of which sensors are online, which features are working
  • Finite State Machines and Transitions: keep track of allowed states and prevent illegal ones

Arrays

• fixed size
• useful for limited memory tasks

Hash Map

• collection of unique elements as key-value pairs. Access them through .first and .secondo