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-rw-r--r--core/math/disjoint_set.cpp31
-rw-r--r--core/math/disjoint_set.h155
2 files changed, 186 insertions, 0 deletions
diff --git a/core/math/disjoint_set.cpp b/core/math/disjoint_set.cpp
new file mode 100644
index 0000000000..838939e1ba
--- /dev/null
+++ b/core/math/disjoint_set.cpp
@@ -0,0 +1,31 @@
+/*************************************************************************/
+/* disjoint_set.h */
+/*************************************************************************/
+/* This file is part of: */
+/* GODOT ENGINE */
+/* https://godotengine.org */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */
+/* */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the */
+/* "Software"), to deal in the Software without restriction, including */
+/* without limitation the rights to use, copy, modify, merge, publish, */
+/* distribute, sublicense, and/or sell copies of the Software, and to */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions: */
+/* */
+/* The above copyright notice and this permission notice shall be */
+/* included in all copies or substantial portions of the Software. */
+/* */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
+/*************************************************************************/
+
+#include "disjoint_set.h"
diff --git a/core/math/disjoint_set.h b/core/math/disjoint_set.h
new file mode 100644
index 0000000000..c9b3d0b65d
--- /dev/null
+++ b/core/math/disjoint_set.h
@@ -0,0 +1,155 @@
+/*************************************************************************/
+/* disjoint_set.h */
+/*************************************************************************/
+/* This file is part of: */
+/* GODOT ENGINE */
+/* https://godotengine.org */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */
+/* */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the */
+/* "Software"), to deal in the Software without restriction, including */
+/* without limitation the rights to use, copy, modify, merge, publish, */
+/* distribute, sublicense, and/or sell copies of the Software, and to */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions: */
+/* */
+/* The above copyright notice and this permission notice shall be */
+/* included in all copies or substantial portions of the Software. */
+/* */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
+/*************************************************************************/
+
+#ifndef DISJOINT_SET_H
+#define DISJOINT_SET_H
+
+#include "core/map.h"
+#include "core/vector.h"
+
+/**
+ @author Marios Staikopoulos <marios@staik.net>
+*/
+
+/* This DisjointSet class uses Find with path compression and Union by rank */
+template <typename T, class C = Comparator<T>, class AL = DefaultAllocator>
+class DisjointSet {
+
+ struct Element {
+ T object;
+ Element *parent = nullptr;
+ int rank = 0;
+ };
+
+ typedef Map<T, Element *, C, AL> MapT;
+
+ MapT elements;
+
+ Element *get_parent(Element *element);
+
+ _FORCE_INLINE_ Element *insert_or_get(T object);
+
+public:
+ ~DisjointSet();
+
+ _FORCE_INLINE_ void insert(T object) { (void)insert_or_get(object); }
+
+ void create_union(T a, T b);
+
+ void get_representatives(Vector<T> &out_roots);
+
+ void get_members(Vector<T> &out_members, T representative);
+};
+
+/* FUNCTIONS */
+
+template <typename T, class C, class AL>
+DisjointSet<T, C, AL>::~DisjointSet() {
+ for (typename MapT::Element *itr = elements.front(); itr != nullptr; itr = itr->next()) {
+ memdelete_allocator<Element, AL>(itr->value());
+ }
+}
+
+template <typename T, class C, class AL>
+typename DisjointSet<T, C, AL>::Element *DisjointSet<T, C, AL>::get_parent(Element *element) {
+ if (element->parent != element) {
+ element->parent = get_parent(element->parent);
+ }
+
+ return element->parent;
+}
+
+template <typename T, class C, class AL>
+typename DisjointSet<T, C, AL>::Element *DisjointSet<T, C, AL>::insert_or_get(T object) {
+ typename MapT::Element *itr = elements.find(object);
+ if (itr != nullptr) {
+ return itr->value();
+ }
+
+ Element *new_element = memnew_allocator(Element, AL);
+ new_element->object = object;
+ new_element->parent = new_element;
+ elements.insert(object, new_element);
+
+ return new_element;
+}
+
+template <typename T, class C, class AL>
+void DisjointSet<T, C, AL>::create_union(T a, T b) {
+
+ Element *x = insert_or_get(a);
+ Element *y = insert_or_get(b);
+
+ Element *x_root = get_parent(x);
+ Element *y_root = get_parent(y);
+
+ // Already in the same set
+ if (x_root == y_root)
+ return;
+
+ // Not in the same set, merge
+ if (x_root->rank < y_root->rank) {
+ SWAP(x_root, y_root);
+ }
+
+ // Merge y_root into x_root
+ y_root->parent = x_root;
+ if (x_root->rank == y_root->rank) {
+ ++x_root->rank;
+ }
+}
+
+template <typename T, class C, class AL>
+void DisjointSet<T, C, AL>::get_representatives(Vector<T> &out_representatives) {
+ for (typename MapT::Element *itr = elements.front(); itr != nullptr; itr = itr->next()) {
+ Element *element = itr->value();
+ if (element->parent == element) {
+ out_representatives.push_back(element->object);
+ }
+ }
+}
+
+template <typename T, class C, class AL>
+void DisjointSet<T, C, AL>::get_members(Vector<T> &out_members, T representative) {
+ typename MapT::Element *rep_itr = elements.find(representative);
+ ERR_FAIL_COND(rep_itr == nullptr);
+
+ Element *rep_element = rep_itr->value();
+ ERR_FAIL_COND(rep_element->parent != rep_element);
+
+ for (typename MapT::Element *itr = elements.front(); itr != nullptr; itr = itr->next()) {
+ Element *parent = get_parent(itr->value());
+ if (parent == rep_element) {
+ out_members.push_back(itr->key());
+ }
+ }
+}
+
+#endif
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