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Commit 7676103

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EgorBurov246EgorBurov246
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Лабораторная работа №27
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‎students/23K0815/23K0815-p27/pom.xml‎

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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<parent>
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<artifactId>23K0815</artifactId>
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<groupId>ru.mirea.practice</groupId>
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<version>2024.1</version>
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<relativePath>../pom.xml</relativePath>
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</parent>
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<artifactId>23K0815-p27</artifactId>
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<description>Массивы</description>
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</project>

‎students/23K0815/23K0815-p27/src/main/java/ru/mirea/practice/s0000001/task1/Application.java‎

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package ru.mirea.practice.s0000001.task1;
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public abstract class Application {
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public static void main(String[] args) {
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SimpleHashTable myHashTable = new SimpleHashTable(10);
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myHashTable.insert("item1", "data1");
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myHashTable.insert("item2", "data2");
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System.out.println(myHashTable.retrieve("item1"));
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myHashTable.remove("item1");
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System.out.println(myHashTable.retrieve("item1"));
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}
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}

‎students/23K0815/23K0815-p27/src/main/java/ru/mirea/practice/s0000001/task1/SimpleHashTable.java‎

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package ru.mirea.practice.s0000001.task1;
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import java.util.LinkedList;
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class SimpleHashTable {
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private LinkedList<HashEntry>[] buckets;
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private int capacity;
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private static class HashEntry {
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String identifier;
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String data;
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HashEntry(String identifier, String data) {
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this.identifier = identifier;
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this.data = data;
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}
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}
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public SimpleHashTable(int capacity) {
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this.capacity = capacity;
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buckets = new LinkedList[capacity];
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for (int i = 0; i < capacity; i++) {
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buckets[i] = new LinkedList<>();
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}
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}
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private int computeHash(String identifier) {
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return Math.abs(identifier.hashCode()) % capacity;
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}
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public void insert(String identifier, String data) {
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int index = computeHash(identifier);
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LinkedList<HashEntry> entries = buckets[index];
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for (HashEntry entry : entries) {
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if (entry.identifier.equals(identifier)) {
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entry.data = data;
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return;
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}
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}
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entries.add(new HashEntry(identifier, data));
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}
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public String retrieve(String identifier) {
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int index = computeHash(identifier);
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LinkedList<HashEntry> entries = buckets[index];
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for (HashEntry entry : entries) {
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if (entry.identifier.equals(identifier)) {
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return entry.data;
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}
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}
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return null;
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}
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public void remove(String identifier) {
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int index = computeHash(identifier);
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LinkedList<HashEntry> entries = buckets[index];
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entries.removeIf(entry -> entry.identifier.equals(identifier));
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}
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public void reset() {
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buckets = new LinkedList[capacity];
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for (int i = 0; i < capacity; i++) {
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buckets[i] = new LinkedList<>();
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}
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}
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}

‎students/23K0815/23K0815-p27/src/main/java/ru/mirea/practice/s0000001/task2/HashTableDemo.java‎

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package ru.mirea.practice.s0000001.task2;
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public abstract class HashTableDemo {
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public static void main(String[] args) {
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MyHashTable myHashTable = new MyHashTable(10);
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myHashTable.insert("item1", "data1");
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myHashTable.insert("item2", "data2");
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myHashTable.insert("item3", "data3");
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myHashTable.insert("item4", "data4");
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myHashTable.insert("item5", "data5");
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myHashTable.insert("item6", "data6");
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myHashTable.insert("item7", "data7");
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myHashTable.insert("item8", "data8");
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myHashTable.insert("item9", "data9");
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myHashTable.insert("item10", "data10");
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System.out.println("Output:");
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for (int i = 1; i <= 10; i++) {
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String identifier = "item" + i;
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String data = myHashTable.retrieve(identifier);
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System.out.println(identifier + ": " + data);
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}
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myHashTable.remove("item5");
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System.out.println("\nAfter removing item5:");
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for (int i = 1; i <= 10; i++) {
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String identifier = "item" + i;
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String data = myHashTable.retrieve(identifier);
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System.out.println(identifier + ": " + data);
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}
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}
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}

‎students/23K0815/23K0815-p27/src/main/java/ru/mirea/practice/s0000001/task2/MyHashTable.java‎

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package ru.mirea.practice.s0000001.task2;
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import java.util.LinkedList;
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class MyHashTable {
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private LinkedList<HashEntry>[] buckets;
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private int capacity;
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private static class HashEntry {
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String identifier;
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String data;
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HashEntry(String identifier, String data) {
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this.identifier = identifier;
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this.data = data;
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}
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}
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public MyHashTable(int capacity) {
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this.capacity = capacity;
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buckets = new LinkedList[capacity];
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for (int i = 0; i < capacity; i++) {
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buckets[i] = new LinkedList<>();
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}
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}
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private int computeHash(String identifier) {
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return Math.abs(identifier.hashCode()) % capacity;
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}
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public void insert(String identifier, String data) {
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int index = computeHash(identifier);
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LinkedList<HashEntry> entries = buckets[index];
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for (HashEntry entry : entries) {
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if (entry.identifier.equals(identifier)) {
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entry.data = data;
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return;
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}
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}
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entries.add(new HashEntry(identifier, data));
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}
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public String retrieve(String identifier) {
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int index = computeHash(identifier);
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LinkedList<HashEntry> entries = buckets[index];
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for (HashEntry entry : entries) {
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if (entry.identifier.equals(identifier)) {
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return entry.data;
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}
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}
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return null;
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}
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public void remove(String identifier) {
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int index = computeHash(identifier);
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LinkedList<HashEntry> entries = buckets[index];
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entries.removeIf(entry -> entry.identifier.equals(identifier));
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}
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public void reset() {
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buckets = new LinkedList[capacity];
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for (int i = 0; i < capacity; i++) {
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buckets[i] = new LinkedList<>();
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}
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}
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}

‎students/23K0815/pom.xml‎

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<module>23K0815-p24</module>
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<module>23K0815-p25</module>
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<module>23K0815-p26</module>
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<module>23K0815-p27</module>
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</modules>
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</project>

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