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/*
 * Copyright (c) 2010-2021 Haifeng Li. All rights reserved.
 *
 * Smile is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Smile is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Smile.  If not, see .
 */

package smile.association;

import java.util.Arrays;

/**
 * A set of items. The support supp(X) of an item set X is defined as the
 * proportion of transactions in the data set which contain the item set.
 * In this class, the support is actually the raw frequency rather than the
 * ratio.
 *
 * @param items The set of items.
 * @param support The associated support value.
 * @author Haifeng Li
 */
public record ItemSet(int[] items, int support) {

    @Override
    public boolean equals(Object o) {
        if (o instanceof ItemSet a) {
            return support == a.support && Arrays.equals(items, a.items);
        }
        
        return false;
    }

    @Override
    public int hashCode() {
        int hash = 7;
        hash = 23 * hash + Arrays.hashCode(this.items);
        hash = 23 * hash + this.support;
        return hash;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();

        sb.append("ItemSet(");
        sb.append(Arrays.toString(items));
        sb.append(", support=");
        sb.append(support);
        sb.append(')');
        
        return sb.toString();
    }
}