76 lines
1.6 KiB
C++
76 lines
1.6 KiB
C++
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __UTIL_DISJOINT_SET_H__
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#define __UTIL_DISJOINT_SET_H__
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#include "util_array.h"
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#include <utility>
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CCL_NAMESPACE_BEGIN
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class DisjointSet {
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private:
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array<size_t> parents;
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array<size_t> ranks;
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public:
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DisjointSet(size_t size) : parents(size), ranks(size)
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{
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for (size_t i = 0; i < size; i++) {
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parents[i] = i;
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ranks[i] = 0;
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}
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}
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size_t find(size_t x)
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{
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size_t root = x;
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while (parents[root] != root) {
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root = parents[root];
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}
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while (parents[x] != root) {
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size_t parent = parents[x];
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parents[x] = root;
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x = parent;
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}
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return root;
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}
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void join(size_t x, size_t y)
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{
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size_t x_root = find(x);
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size_t y_root = find(y);
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if (x_root == y_root) {
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return;
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}
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if (ranks[x_root] < ranks[y_root]) {
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std::swap(x_root, y_root);
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}
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parents[y_root] = x_root;
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if (ranks[x_root] == ranks[y_root]) {
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ranks[x_root]++;
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}
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}
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};
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CCL_NAMESPACE_END
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#endif /* __UTIL_DISJOINT_SET_H__ */
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