61 lines
1.0 KiB
C++
61 lines
1.0 KiB
C++
/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0 */
|
|
|
|
#pragma once
|
|
|
|
#include "util/array.h"
|
|
#include <utility>
|
|
|
|
CCL_NAMESPACE_BEGIN
|
|
|
|
class DisjointSet {
|
|
private:
|
|
array<size_t> parents;
|
|
array<size_t> ranks;
|
|
|
|
public:
|
|
DisjointSet(const size_t size) : parents(size), ranks(size)
|
|
{
|
|
for (size_t i = 0; i < size; i++) {
|
|
parents[i] = i;
|
|
ranks[i] = 0;
|
|
}
|
|
}
|
|
|
|
size_t find(size_t x)
|
|
{
|
|
size_t root = x;
|
|
while (parents[root] != root) {
|
|
root = parents[root];
|
|
}
|
|
while (parents[x] != root) {
|
|
const size_t parent = parents[x];
|
|
parents[x] = root;
|
|
x = parent;
|
|
}
|
|
return root;
|
|
}
|
|
|
|
void join(const size_t x, const size_t y)
|
|
{
|
|
size_t x_root = find(x);
|
|
size_t y_root = find(y);
|
|
|
|
if (x_root == y_root) {
|
|
return;
|
|
}
|
|
|
|
if (ranks[x_root] < ranks[y_root]) {
|
|
std::swap(x_root, y_root);
|
|
}
|
|
parents[y_root] = x_root;
|
|
|
|
if (ranks[x_root] == ranks[y_root]) {
|
|
ranks[x_root]++;
|
|
}
|
|
}
|
|
};
|
|
|
|
CCL_NAMESPACE_END
|