29 lines
747 B
Java
29 lines
747 B
Java
// onjava/Sets.java
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package onjava;
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import java.util.*;
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public class Sets {
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public static <T> Set<T> union(Set<T> a, Set<T> b) {
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Set<T> result = new HashSet<>(a);
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result.addAll(b);
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return result;
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}
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public static <T>
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Set<T> intersection(Set<T> a, Set<T> b) {
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Set<T> result = new HashSet<>(a);
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result.retainAll(b);
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return result;
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}
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// Subtract subset from superset:
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public static <T> Set<T>
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difference(Set<T> superset, Set<T> subset) {
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Set<T> result = new HashSet<>(superset);
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result.removeAll(subset);
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return result;
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}
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// Reflexive--everything not in the intersection:
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public static <T> Set<T> complement(Set<T> a, Set<T> b) {
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return difference(union(a, b), intersection(a, b));
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}
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}
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