Java05. ДЗ 01, Егоров Антон

hw_01/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>1</groupId>
+  <artifactId>hw_01</artifactId>
+  <version>0.0.1-SNAPSHOT</version>
+  <packaging>jar</packaging>
+
+  <name>hw_01</name>
+  <url>http://maven.apache.org</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <source>1.8</source>
+    <target>1.8</target>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>3.8.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>

hw_01/src/main/java/hw_01/Bor.java

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+package hw_01;
+
+public class Bor implements Trie {
+	final private Node bor;
+	private int size = 0;
+
+	public Bor() {
+		bor = new Node();
+	}
+
+	public boolean add(String element) {
+		if (contains(element)) {
+			return false;
+		}
+
+		Node p = bor;
+
+		p.nwords++;
+		for (int i = 0; i < element.length(); i++) {
+			int currIdx = arrNum(element.charAt(i));
+
+			if (p.lifes[currIdx] == null) {
+				p.lifes[currIdx] = new Node();
+				size++;
+			}
+			p = p.lifes[currIdx];
+			p.nwords++;
+		}
+
+		p.isTerminal = true;
+		return true;
+	}
+
+	public boolean contains(String element) {
+		Node p = bor;
+		for (int i = 0; i < element.length(); i++) {
+			int currIdx = arrNum(element.charAt(i));
+
+			if (p.lifes[currIdx] == null) {
+				return false;
+			}
+			p = p.lifes[currIdx];
+		}
+
+		return p.isTerminal;
+	}
+
+	public boolean remove(String element) {
+		if (!contains(element)) {
+			return false;
+		}
+
+		Node p = bor;
+		p.nwords--;
+		for (int i = 0; i < element.length(); i++) {
+			int currIdx = arrNum(element.charAt(i));
+
+			if (p.lifes[currIdx].nwords == 1) {
+				size -= element.length() - i;
+				p.lifes[currIdx] = null;
+				return true;
+			}
+			p = p.lifes[currIdx];
+			p.nwords--;
+		}
+
+		p.isTerminal = false;
+
+		return true;
+	}
+
+	public int size() {
+		return size;
+	}
+
+	public int howManyStartsWithPrefix(String prefix) {
+		Node p = bor;
+		for (int i = 0; i < prefix.length(); i++) {
+			int currIdx = arrNum(prefix.charAt(i));
+
+			if (p.lifes[currIdx] == null) {
+				return 0;
+			}
+			p = p.lifes[currIdx];
+		}
+
+		return p.nwords;
+	}
+
+	private int arrNum(char a) {
+		if ('a' <= a && a <= 'z') {
+			return a - 'a';
+		}
+
+		if ('A' <= a && a <= 'Z') {
+			return a - 'A' + 'z' - 'a' + 1;
+		}
+
+		return -1;
+	}
+
+	private class Node {
+		public boolean isTerminal;
+		public int nwords;
+		Node[] lifes = new Node[2*('z' - 'a' + 1)];
+	}
+}

hw_01/src/main/java/hw_01/Trie.java

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+package hw_01;
+
+public interface Trie {
+
+    /**
+     * Expected complexity: O(|element|)
+     * @return <tt>true</tt> if this set did not already contain the specified
+     *         element
+     */
+    boolean add(String element);
+
+    /**
+     * Expected complexity: O(|element|)
+     */
+    boolean contains(String element);
+
+    /**
+     * Expected complexity: O(|element|)
+     * @return <tt>true</tt> if this set contained the specified element
+     */
+    boolean remove(String element);
+
+    /**
+     * Expected complexity: O(1)
+     */
+    int size();
+
+    /**
+     * Expected complexity: O(|prefix|)
+     */
+    int howManyStartsWithPrefix(String prefix);
+}

hw_01/src/test/java/hw_01/TrieImplTest.java

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+package hw_01;
+
+import junit.framework.TestCase;
+
+public class TrieImplTest extends TestCase {
+	private Bor b;
+
+	public void setUp() {
+		b = new Bor();
+	}
+
+	public void testAddSizeContains() {
+		assertFalse(b.contains("Hello"));
+		assertTrue(b.add("Hello"));
+		assertTrue(b.contains("Hello"));
+		assertEquals(5, b.size());
+		assertEquals(1, b.howManyStartsWithPrefix("Hell"));
+	}
+
+	public void testAddContainsPrefix() {
+		b.add("Hello");
+		assertFalse(b.contains("Hell"));
+		assertTrue(b.add("Hell"));
+		assertTrue(b.contains("Hell"));
+		assertEquals(5, b.size());
+		assertEquals(2, b.howManyStartsWithPrefix("Hell"));
+	}
+
+	public void testAddOutstandingWord() {
+		b.add("Hello");
+		assertTrue(b.add("Head"));
+		assertEquals(7, b.size());
+	}
+
+	public void testRemovePrefix() {
+		b.add("Hello");
+		b.add("Hell");
+		assertFalse(b.remove("He"));
+		assertTrue(b.remove("Hell"));
+		assertEquals(5, b.size());
+		assertEquals(1, b.howManyStartsWithPrefix("Hell"));
+	}
+
+	public void testTemoveSuffix() {
+		b.add("Hello");
+		b.add("Hell");
+		assertTrue(b.remove("Hello"));
+		assertEquals(4, b.size());
+	}
+/*
+	public void testBorBigTest() {
+		//b = new Bor();
+		//Добавление
+		assertFalse(b.contains("Hello"));
+		assertTrue(b.add("Hello"));
+		assertTrue(b.contains("Hello"));
+		assertEquals(5, b.size());
+		assertFalse(b.add("Hello"));
+		assertEquals(5, b.size());
+		assertFalse(b.contains("Hell"));
+		assertTrue(b.add("Hell"));
+		assertTrue(b.contains("Hell"));
+		assertEquals(5, b.size());
+		assertFalse(b.add("Hell"));
+		assertEquals(5, b.size());
+		assertFalse(b.contains("Head"));
+		assertTrue(b.add("Head"));
+		assertTrue(b.contains("Head"));
+		assertEquals(7, b.size());
+		assertFalse(b.contains(""));
+		assertTrue(b.add(""));
+		assertTrue(b.contains(""));
+		assertEquals(7, b.size());
+
+		//Проверка префиксов
+		assertEquals(3, b.howManyStartsWithPrefix("H"));
+		assertEquals(4, b.howManyStartsWithPrefix(""));
+		assertEquals(1, b.howManyStartsWithPrefix("Hea"));
+		assertEquals(2, b.howManyStartsWithPrefix("Hell"));
+		assertEquals(0, b.howManyStartsWithPrefix("h"));
+
+		//Удаление
+		assertFalse(b.remove("h"));
+		assertFalse(b.remove("H"));
+		assertTrue(b.remove("Hell"));
+		assertFalse(b.remove("Hell"));
+		assertFalse(b.contains("Hell"));
+		assertEquals(7, b.size());
+		assertEquals(1, b.howManyStartsWithPrefix("Hell"));
+
+		assertTrue(b.remove(""));
+		assertFalse(b.remove(""));
+		assertEquals(7, b.size());
+		assertEquals(2, b.howManyStartsWithPrefix(""));
+
+		assertTrue(b.remove("Hello"));
+		assertFalse(b.remove("Hello"));
+		assertEquals(4, b.size());
+
+		assertTrue(b.contains("Head"));
+		assertTrue(b.add("HeadZzZ"));
+		assertEquals(7, b.size());
+		assertEquals(2, b.howManyStartsWithPrefix("Head"));
+		assertEquals(1, b.howManyStartsWithPrefix("HeadZzZ"));
+		assertFalse(b.remove("HeadZ"));
+		assertTrue(b.remove("HeadZzZ"));
+		assertEquals(4, b.size());
+		assertEquals(1, b.howManyStartsWithPrefix("Head"));
+		assertEquals(1, b.howManyStartsWithPrefix(""));
+		assertEquals(0, b.howManyStartsWithPrefix("HeadZ"));
+
+		assertTrue(b.remove("Head"));
+		assertEquals(0, b.size());
+	}
+*/
+}