title: Tree backends documentation_of: //src/atcoder/extra/structure/tree_backends.nim

Tree backends

Nim-ACL has several low-level tree backends for ordered sets, sequence operations, and lazy propagation.

If you need a normal ordered set or map, start with sorted_set_map.

import atcoder/extra/structure/sorted_set_map

Recommended user-facing module

sorted_set_map

import atcoder/extra/structure/sorted_set_map

This is the recommended ordered set/map interface.

Main container types:

SortedSet(K)
SortedMultiSet(K)
SortedMap(K, V)
SortedMultiMap(K, V)

Compatibility alias

set_map

import atcoder/extra/structure/set_map

set_map is a compatibility alias for sorted_set_map.
For new code, prefer sorted_set_map.

Low-level backends

The following modules are low-level or advanced tree backends:

import atcoder/extra/structure/red_black_tree
import atcoder/extra/structure/randomized_binary_search_tree_with_parent
import atcoder/extra/structure/splay_tree

RedBlackTree

The default backend of sorted_set_map.
It exposes low-level node operations, so most users do not need to import it directly.

RandomizedBinarySearchTree

A backend useful when you want to work directly with sequence operations and split/merge.

SplayTree

A backend for sequence operations, reversal, and lazy propagation.

Notes

Importing multiple low-level backend modules together can cause ambiguous names.
Import only the backend you actually need.

This tree_backends module is documentation-only and intentionally does not re-export low-level backends.