aanzet hash table

datastructures/datastructures.iml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module-library" scope="TEST">
+      <library name="JUnit5.0">
+        <CLASSES>
+          <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-api/5.0.0/junit-jupiter-api-5.0.0.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/apiguardian/apiguardian-api/1.0.0/apiguardian-api-1.0.0.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.0.0/opentest4j-1.0.0.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-commons/1.0.0/junit-platform-commons-1.0.0.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
+  </component>
+</module>

datastructures/src/be/brainbaking/datastructures/hashing/DoubleProbeHash.java

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+package be.brainbaking.datastructures.hashing;
+
+public class DoubleProbeHash implements Hashable {
+
+    private final int max;
+
+    public DoubleProbeHash(int max) {
+        this.max = max;
+    }
+
+    private int auxiliarHash(Object key, int probeStep) {
+        return (1 + key.hashCode()) * (max - 1);
+    }
+
+    @Override
+    public int hash(Object key, int probeStep) {
+        return (auxiliarHash(key, probeStep) + probeStep) % max;
+    }
+}

datastructures/src/be/brainbaking/datastructures/hashing/Hashable.java

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+package be.brainbaking.datastructures.hashing;
+
+public interface Hashable {
+
+    int hash(Object key, int i);
+
+}

datastructures/src/be/brainbaking/datastructures/hashing/LinearProbeHash.java

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+package be.brainbaking.datastructures.hashing;
+
+public class LinearProbeHash implements Hashable {
+
+    private final int max;
+
+    public LinearProbeHash(int max) {
+        this.max = max;
+    }
+
+    @Override
+    public int hash(Object key, int probeStep) {
+        return (key.hashCode() + probeStep) % max;
+    }
+}

datastructures/src/be/brainbaking/datastructures/hashing/QuadraticProbeHash.java

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+package be.brainbaking.datastructures.hashing;
+
+public class QuadraticProbeHash implements Hashable {
+
+    private final int max;
+
+    public QuadraticProbeHash(int max) {
+        this.max = max;
+    }
+
+    @Override
+    public int hash(Object key, int probeStep) {
+        return (key.hashCode() + probeStep * probeStep) % max;
+    }
+}

datastructures/src/be/brainbaking/datastructures/hashtable/HashBucket.java

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+package be.brainbaking.datastructures.hashtable;
+
+public class HashBucket<T> {
+
+    private final T key;
+
+    public HashBucket(T key) {
+        this.key = key;
+    }
+}

datastructures/src/be/brainbaking/datastructures/hashtable/HashTable.java

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+package be.brainbaking.datastructures.hashtable;
+
+import be.brainbaking.datastructures.hashing.Hashable;
+import be.brainbaking.datastructures.hashing.LinearProbeHash;
+
+public class HashTable<T> {
+
+    private final HashBucket<T>[] table;
+    private final Hashable hasher;
+
+    public HashTable() {
+        this(10);
+    }
+
+    private HashTable(int initialSize) {
+        table = new HashBucket[10];
+        hasher = new LinearProbeHash(10);
+    }
+
+    public void add(T key) {
+        add(key, 0);
+    }
+
+    public void remove(T key) {
+        throw new UnsupportedOperationException();
+        // TODO "deleted" stuff
+    }
+
+    public int search(T key) {
+        throw new UnsupportedOperationException();
+        // TODO return key if exists
+    }
+
+    private void add(T key, int probeStep) {
+        if(probeStep > table.length) {
+            throw new UnsupportedOperationException("unable to add key to table, everything occupied?");
+        }
+
+        int hash = hasher.hash(key, probeStep);
+        if(table[hash] != null) {
+            add(key, probeStep + 1);
+        } else {
+            table[hash] = new HashBucket<>(key);
+        }
+
+    }
+
+}

datastructures/test/be/brainbaking/datastructures/hashtable/HashTableTest.java

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+package be.brainbaking.datastructures.hashtable;
+
+import org.junit.jupiter.api.Test;
+
+public class HashTableTest {
+
+    @Test
+    public void add() {
+
+    }
+
+}