0be6d925dc
Which means that reduz' beloved style which we all became used to will now be changed automatically to remove the first empty line. This makes us lean closer to 1TBS (the one true brace style) instead of hybridating it with some Allman-inspired spacing. There's still the case of braces around single-statement blocks that needs to be addressed (but clang-format can't help with that, but clang-tidy may if we agree about it). Part of #33027.
154 lines
5.2 KiB
C++
154 lines
5.2 KiB
C++
/*************************************************************************/
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/* disjoint_set.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef DISJOINT_SET_H
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#define DISJOINT_SET_H
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#include "core/map.h"
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#include "core/vector.h"
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/**
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@author Marios Staikopoulos <marios@staik.net>
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*/
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/* This DisjointSet class uses Find with path compression and Union by rank */
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template <typename T, class C = Comparator<T>, class AL = DefaultAllocator>
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class DisjointSet {
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struct Element {
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T object;
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Element *parent = nullptr;
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int rank = 0;
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};
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typedef Map<T, Element *, C, AL> MapT;
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MapT elements;
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Element *get_parent(Element *element);
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_FORCE_INLINE_ Element *insert_or_get(T object);
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public:
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~DisjointSet();
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_FORCE_INLINE_ void insert(T object) { (void)insert_or_get(object); }
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void create_union(T a, T b);
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void get_representatives(Vector<T> &out_roots);
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void get_members(Vector<T> &out_members, T representative);
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};
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/* FUNCTIONS */
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template <typename T, class C, class AL>
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DisjointSet<T, C, AL>::~DisjointSet() {
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for (typename MapT::Element *itr = elements.front(); itr != nullptr; itr = itr->next()) {
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memdelete_allocator<Element, AL>(itr->value());
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}
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}
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template <typename T, class C, class AL>
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typename DisjointSet<T, C, AL>::Element *DisjointSet<T, C, AL>::get_parent(Element *element) {
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if (element->parent != element) {
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element->parent = get_parent(element->parent);
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}
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return element->parent;
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}
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template <typename T, class C, class AL>
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typename DisjointSet<T, C, AL>::Element *DisjointSet<T, C, AL>::insert_or_get(T object) {
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typename MapT::Element *itr = elements.find(object);
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if (itr != nullptr) {
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return itr->value();
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}
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Element *new_element = memnew_allocator(Element, AL);
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new_element->object = object;
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new_element->parent = new_element;
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elements.insert(object, new_element);
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return new_element;
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}
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template <typename T, class C, class AL>
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void DisjointSet<T, C, AL>::create_union(T a, T b) {
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Element *x = insert_or_get(a);
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Element *y = insert_or_get(b);
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Element *x_root = get_parent(x);
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Element *y_root = get_parent(y);
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// Already in the same set
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if (x_root == y_root)
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return;
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// Not in the same set, merge
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if (x_root->rank < y_root->rank) {
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SWAP(x_root, y_root);
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}
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// Merge y_root into x_root
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y_root->parent = x_root;
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if (x_root->rank == y_root->rank) {
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++x_root->rank;
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}
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}
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template <typename T, class C, class AL>
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void DisjointSet<T, C, AL>::get_representatives(Vector<T> &out_representatives) {
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for (typename MapT::Element *itr = elements.front(); itr != nullptr; itr = itr->next()) {
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Element *element = itr->value();
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if (element->parent == element) {
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out_representatives.push_back(element->object);
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}
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}
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}
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template <typename T, class C, class AL>
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void DisjointSet<T, C, AL>::get_members(Vector<T> &out_members, T representative) {
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typename MapT::Element *rep_itr = elements.find(representative);
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ERR_FAIL_COND(rep_itr == nullptr);
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Element *rep_element = rep_itr->value();
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ERR_FAIL_COND(rep_element->parent != rep_element);
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for (typename MapT::Element *itr = elements.front(); itr != nullptr; itr = itr->next()) {
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Element *parent = get_parent(itr->value());
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if (parent == rep_element) {
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out_members.push_back(itr->key());
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}
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}
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}
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#endif // DISJOINT_SET_H
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