JavaArithmetic/src/datastructure/map/LinkedListMap.java at master · git-jhy/JavaArithmetic · GitHub

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package datastructure.map;

import java.util.ArrayList;

public class LinkedListMap<K, V> implements Map<K, V> {

private class Node{

public K key;

public V value;

public Node next;

public Node(K key, V value, Node next){

this.key = key;

this.value = value;

this.next = next;

}

public Node(K key, V value){

this(key, value, null);

}

public Node(){

this(null, null, null);

}

@Override

public String toString(){

return key.toString() + " : " + value.toString();

}

private Node dummyHead;

private int size;

public LinkedListMap(){

dummyHead = new Node();

size = 0;

}

@Override

public int getSize(){

return size;

}

@Override

public boolean isEmpty(){

return size == 0;

}

private Node getNode(K key){

Node cur = dummyHead.next;

while(cur != null){

if(cur.key.equals(key))

return cur;

cur = cur.next;

}

return null;

}

@Override

public boolean contains(K key){

return getNode(key) != null;

}

@Override

public V get(K key){

Node node = getNode(key);

return node == null ? null : node.value;

}

@Override

public void add(K key, V value){

Node node = getNode(key);

if(node == null){

dummyHead.next = new Node(key, value, dummyHead.next);

size ++;

}

else

node.value = value;

}

@Override

public void set(K key, V newValue){

Node node = getNode(key);

if(node == null)

throw new IllegalArgumentException(key + " doesn't exist!");

node.value = newValue;

}

@Override

public V remove(K key){

Node prev = dummyHead;

while(prev.next != null){

if(prev.next.key.equals(key))

break;

prev = prev.next;

}

if(prev.next != null){

Node delNode = prev.next;

prev.next = delNode.next;

delNode.next = null;

size --;

return delNode.value;

}

return null;

}

public static void main(String[] args){

System.out.println("Pride and Prejudice");

ArrayList<String> words = new ArrayList<>();

if(FileOperation.readFile("pride-and-prejudice.txt", words)) {

System.out.println("Total words: " + words.size());

LinkedListMap<String, Integer> map = new LinkedListMap<>();

for (String word : words) {

if (map.contains(word))

map.set(word, map.get(word) + 1);

else

map.add(word, 1);

}

System.out.println("Total different words: " + map.getSize());

System.out.println("Frequency of PRIDE: " + map.get("pride"));

System.out.println("Frequency of PREJUDICE: " + map.get("prejudice"));

}

System.out.println();

}

JavaArithmetic/src/datastructure/map/LinkedListMap.java at master · git-jhy/JavaArithmetic · GitHub

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