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Open-source constraint solver.
/*
* This file is part of choco-solver, http://choco-solver.org/
*
* Copyright (c) 2023, IMT Atlantique. All rights reserved.
*
* Licensed under the BSD 4-clause license.
*
* See LICENSE file in the project root for full license information.
*/
package org.chocosolver.util.objects;
import org.chocosolver.memory.IEnvironment;
import org.chocosolver.memory.IStateInt;
/**
* Implementation based on "Maintaining GAC on adhoc r-ary constraints", Cheng and Yap, CP12.
*
*
* Created by cprudhom on 04/11/14.
* Project: choco.
*/
public class StoredSparseSet {
private int[] sparse;
private int[] dense;
private final IStateInt members;
public StoredSparseSet(IEnvironment environment) {
members = environment.makeInt(0);
sparse = new int[16];
dense = new int[16];
}
/**
* Return if a value is contained.
*
* @param k the value to test
* @return true if `k` is contained, false otherwise
*/
public boolean contains(int k) {
if (k < sparse.length) {
int a = sparse[k];
return a < members.get() && dense[a] == k;
} else return false;
}
/**
* Add the value `k` to the set.
*
* @param k value to add
*/
public void add(int k) {
ensureCapacity(k+1);
int a = sparse[k];
int b = members.get();
if (a >= b || dense[a] != k) {
sparse[k] = b;
dense[b] = k;
members.set(b + 1);
}
}
private void ensureCapacity(int k) {
if (k > sparse.length) {
int[] tmp = sparse;
int nsize = Math.max(k+1, tmp.length * 3 / 2 + 1);
sparse = new int[nsize];
sparse = new int[nsize];
System.arraycopy(tmp, 0, sparse, 0, tmp.length);
tmp = dense;
dense = new int[nsize];
System.arraycopy(tmp, 0, dense, 0, tmp.length);
}
}
}