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42 lines
1.1 KiB
42 lines
1.1 KiB
// Copyright 2018 PingCAP, Inc.
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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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// See the License for the specific language governing permissions and
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// limitations under the License.
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package disjointset
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// IntSet is the int disjoint set.
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type IntSet struct {
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parent []int
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}
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// NewIntSet returns a new int disjoint set.
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func NewIntSet(size int) *IntSet {
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p := make([]int, size)
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for i := range p {
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p[i] = i
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}
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return &IntSet{parent: p}
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}
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// Union unions two sets in int disjoint set.
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func (m *IntSet) Union(a int, b int) {
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m.parent[m.FindRoot(a)] = m.FindRoot(b)
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}
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// FindRoot finds the representative element of the set that `a` belongs to.
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func (m *IntSet) FindRoot(a int) int {
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if a == m.parent[a] {
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return a
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}
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m.parent[a] = m.FindRoot(m.parent[a])
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return m.parent[a]
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}
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