blob: 57688867046af9800135a52bb7dae2382b24d148 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
#pragma once
#include <util/system/yassert.h>
#include <util/generic/vector.h>
// Implementation of disjoint-set data structure with union by rank and path compression.
// See http://en.wikipedia.org/wiki/Disjoint-set_data_structure
class TDisjointSets {
public:
using TElement = size_t;
private:
mutable TVector<TElement> Parents;
TVector<size_t> Ranks;
TVector<size_t> Sizes;
size_t NumberOfSets;
public:
TDisjointSets(size_t setCount)
: Parents(setCount)
, Ranks(setCount, 0)
, Sizes(setCount, 1)
, NumberOfSets(setCount)
{
for (size_t i = 0; i < setCount; ++i)
Parents[i] = i;
}
TElement CanonicSetElement(TElement item) const {
if (Parents[item] != item)
Parents[item] = CanonicSetElement(Parents[item]);
return Parents[item];
}
size_t SizeOfSet(TElement item) const {
return Sizes[CanonicSetElement(item)];
}
size_t InitialSetCount() const {
return Parents.size();
}
size_t SetCount() const {
return NumberOfSets;
}
void UnionSets(TElement item1, TElement item2) {
TElement canonic1 = CanonicSetElement(item1);
TElement canonic2 = CanonicSetElement(item2);
if (canonic1 == canonic2)
return;
--NumberOfSets;
if (Ranks[canonic1] < Ranks[canonic2]) {
Parents[canonic1] = canonic2;
Sizes[canonic2] += Sizes[canonic1];
} else {
Parents[canonic2] = canonic1;
Sizes[canonic1] += Sizes[canonic2];
Ranks[canonic2] += Ranks[canonic1] == Ranks[canonic2] ? 1 : 0;
}
}
void Expand(size_t setCount) {
if (setCount < Parents.size()) {
return;
}
size_t prevSize = Parents.size();
Parents.resize(setCount);
Ranks.resize(setCount);
Sizes.resize(setCount);
NumberOfSets += setCount - prevSize;
for (size_t i = prevSize; i < setCount; ++i) {
Parents[i] = i;
Ranks[i] = 0;
Sizes[i] = 1;
}
}
};
|
