Hash table with separate chaining
import java.io.IOException;
class Link {
private int data;
public Link next;
public Link(int d) {
data = d;
}
public int getKey() {
return data;
}
public void displayLink() {
System.out.print(data + " ");
}
}
class SortedList {
private Link first;
public SortedList() {
first = null;
}
public void insert(Link theLink){
int key = theLink.getKey();
Link previous = null; // start at first
Link current = first;
// until end of list,
//or current bigger than key,
while (current != null && key > current.getKey()) {
previous = current;
current = current.next; // go to next item
}
if (previous == null) // if beginning of list,
first = theLink;
else
// not at beginning,
previous.next = theLink;
theLink.next = current;
}
public void delete(int key){
Link previous = null;
Link current = first;
while (current != null && key != current.getKey()) {
previous = current;
current = current.next;
}
// disconnect link
if (previous == null) // if beginning of list delete first link
first = first.next;
else
// not at beginning
previous.next = current.next; //delete current link
}
public Link find(int key) {
Link current = first;
while (current != null && current.getKey() <= key) { // or key too small,
if (current.getKey() == key) // found, return link
return current;
current = current.next; // go to next item
}
return null; // cannot find it
}
public void displayList() {
System.out.print("List: ");
Link current = first;
while (current != null){
current.displayLink();
current = current.next;
}
System.out.println("");
}
}
public class HashChain {
private SortedList[] hashArray;
private int arraySize;
public HashChain(int size) {
arraySize = size;
hashArray = new SortedList[arraySize];
for (int i = 0; i < arraySize; i++)
hashArray[i] = new SortedList();
}
public void displayTable() {
for (int j = 0; j < arraySize; j++) {
System.out.print(j + ". ");
hashArray[j].displayList();
}
}
public int hashFunc(int key) {
return key % arraySize;
}
public void insert(Link theLink) {
int key = theLink.getKey();
int hashVal = hashFunc(key);
hashArray[hashVal].insert(theLink);
}
public void delete(int key) {
int hashVal = hashFunc(key); // hash the key
hashArray[hashVal].delete(key);
}
public Link find(int key) {
int hashVal = hashFunc(key); // hash the key
Link theLink = hashArray[hashVal].find(key); // get link
return theLink;
}
public static void main(String[] args) throws IOException {
int aKey;
Link dataItem;
int size, initSize, keysPerCell = 100;
size = 100;
initSize = 10;
HashChain hashTable = new HashChain(size);
for (int i = 0; i < initSize; i++){
aKey = (int) (java.lang.Math.random() * keysPerCell * size);
dataItem = new Link(aKey);
hashTable.insert(dataItem);
}
hashTable.displayTable();
aKey = 100;
dataItem = new Link(aKey);
hashTable.insert(dataItem);
aKey = 100;
hashTable.delete(aKey);
aKey = 50;
dataItem = hashTable.find(aKey);
if (dataItem != null)
System.out.println("Found " + aKey);
else
System.out.println("Could not find " + aKey);
}
}
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