import java.lang.reflect.Array;
@SuppressWarnings("unchecked")
public class HashMap {
class Node {
K key;
V value;
Node next;
}
private static final int SIZE = 10;
private Node[] map;
private Node[] tail;
private int size;
public HashMap() {
this(SIZE);
}
public HashMap(int size) {
this.size = size;
map = (Node[]) Array.newInstance(Node.class, size);
tail = (Node[]) Array.newInstance(Node.class, size);
}
public void put(K key, V value) {
int index = getIndex(key);
Node newNode = new Node();
newNode.key = key;
newNode.value = value;
if (tail[index] == null) {
map[index] = newNode;
tail[index] = newNode;
} else {
tail[index].next = newNode;
tail[index] = newNode;
}
}
public V get(K key) {
int index = getIndex(key);
Node head = map[index];
while (head != null && !head.key.equals(key))
head = head.next;
if (head.key.equals(key))
return head.value;
else
return null;
}
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("[");
for (int i = 0; i < size; i++) {
Node head = map[i];
sb.append("\n");
if (head != null) {
sb.append("\t[" + i + "] -> {" + head.key + " -> " + head.value + "}");
head = head.next;
while (head != null) {
sb.append(" -> {" + head.key + " -> " + head.value + "}");
head = head.next;
}
} else {
sb.append("\t[" + i + "] -> null");
}
}
sb.append("\n\b]");
return sb.toString();
}
int getIndex(K key) {
int hashCode = hashCode(key);
return hashCode % size;
}
int hashCode(K key) {
return key.hashCode();
}
boolean equals(Node node1, Node node2) {
return node1.key.equals(node2.key);
}
public static void main(String[] args) {
HashMap hm = new HashMap<>();
hm.put("one", 1);
hm.put("two", 2);
hm.put("three", 3);
hm.put("four", 4);
hm.put("five", 5);
hm.put("six", 6);
hm.put("seven", 7);
hm.put("eight", 8);
hm.put("nine", 9);
hm.put("ten", 10);
System.out.println(hm);
HashMap hm1 = new HashMap<>();
hm1.put("one", 'a');
hm1.put("two", 'b');
hm1.put("three", 'c');
hm1.put("four", 'd');
hm1.put("five", 'e');
hm1.put("six", 'f');
hm1.put("seven", 'g');
hm1.put("eight", 'h');
hm1.put("nine", 'i');
hm1.put("ten", 'j');
System.out.println(hm1);
}
}