284 lines
6.3 KiB
Java
284 lines
6.3 KiB
Java
<<<<<<< HEAD:Data Structures/HashMap/HashMap.java
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import java.util.ArrayList;
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import java.util.LinkedList;
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public class HashMap<K,V> {
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public class hmnodes{ //HashMap nodes
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K key;
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V value;
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}
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private int size=0; //size of hashmap
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private LinkedList<hmnodes> buckets[]; //array of addresses of list
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public HashMap(){
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buckets=new LinkedList[4]; //initially create bucket of any size
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for(int i=0;i<4;i++)
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buckets[i]=new LinkedList<>();
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}
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public void put(K key,V value) throws Exception{
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int bi=bucketIndex(key); //find the index,the new key will be inserted in linklist at that index
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int fountAt=find(bi,key); //check if key already exists or not
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if(fountAt==-1){
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hmnodes temp=new hmnodes(); //if doesn't exist create new node and insert
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temp.key=key;
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temp.value=value;
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buckets[bi].addLast(temp);
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this.size++;
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}else{
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buckets[bi].get(fountAt).value=value;//if already exist modify the value
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}
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double lambda = (this.size*1.0)/this.buckets.length;
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if(lambda>2.0){
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rehash(); //rehashing function which will increase the size of bucket as soon as lambda exceeds 2.0
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}
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return;
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}
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public V get(K key) throws Exception{
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int bi=bucketIndex(key);
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int fountAt=find(bi,key);
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if(fountAt==-1){
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return null;
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}else{
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return buckets[bi].get(fountAt).value;
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}
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}
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public V remove(K key) throws Exception{
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int bi=bucketIndex(key);
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int fountAt=find(bi,key);
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if(fountAt==-1){
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return null;
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}else{
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this.size--;
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return buckets[bi].remove(fountAt).value;
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}
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}
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public boolean containskey(K key) throws Exception{
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int bi=bucketIndex(key);
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int fountAt=find(bi,key);
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if(fountAt==-1){
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return false;
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}else{
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return true;
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}
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}
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public int size(){
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return this.size;
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}
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public boolean isempty(){
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return this.size==0;
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}
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public ArrayList<K> keyset() throws Exception{
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ArrayList<K> arr=new ArrayList<>();
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for(int i=0;i<buckets.length;i++){
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for(int j=0;j<buckets[i].size();j++){
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arr.add(buckets[i].get(j).key);
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}
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}
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return arr;
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}
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public ArrayList<V> valueset() throws Exception{
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ArrayList<V> arr=new ArrayList<>();
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for(int i=0;i<buckets.length;i++){
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for(int j=0;j<buckets[i].size();j++){
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arr.add(buckets[i].get(j).value);
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}
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}
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return arr;
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}
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public void display() throws Exception{
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for(int i=0;i<buckets.length;i++){
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System.out.print("Bucket: "+i+" ");
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for(int j=0;j<buckets[i].size();j++){
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hmnodes temp=buckets[i].get(j);
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System.out.print("["+temp.key+"->"+temp.value+"]");
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}
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System.out.println();
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}
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}
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public int find(int bi,K key) throws Exception{
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for(int i=0;i<buckets[bi].size();i++){
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if(key.equals(buckets[bi].get(i).key))
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return i;
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}
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return -1;
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}
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public int bucketIndex(K key) throws Exception{
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int bi=key.hashCode();
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return Math.abs(bi%buckets.length);
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}
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private void rehash() throws Exception{
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LinkedList<hmnodes> ob[]= buckets;
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buckets=new LinkedList[ob.length*2];
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for(int i=0;i<ob.length*2;i++)
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buckets[i]=new LinkedList<>();
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size = 0;
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for(int i=0;i<ob.length;i++){
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for(int j=0;j<ob[i].size();j++){
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put(ob[i].get(j).key,ob[i].get(j).value);
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}
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}
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}
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}
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=======
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import java.util.ArrayList;
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import java.util.LinkedList;
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public class HashMap<K,V> {
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public class hmnodes{ //HashMap nodes
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K key;
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V value;
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}
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private int size=0; //size of hashmap
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private LinkedList<hmnodes> buckets[]; //array of addresses of list
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|
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public HashMap(){
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buckets=new LinkedList[4]; //initially create bucket of any size
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for(int i=0;i<4;i++)
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buckets[i]=new LinkedList<>();
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}
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public void put(K key,V value) throws Exception{
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int bi=bucketIndex(key); //find the index,the new key will be inserted in linklist at that index
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int fountAt=find(bi,key); //check if key already exists or not
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if(fountAt==-1){
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hmnodes temp=new hmnodes(); //if doesn't exist create new node and insert
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temp.key=key;
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temp.value=value;
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buckets[bi].addLast(temp);
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this.size++;
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}else{
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buckets[bi].get(fountAt).value=value;//if already exist modify the value
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}
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double lambda = (this.size*1.0)/this.buckets.length;
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if(lambda>2.0){
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rehash(); //rehashing function which will increase the size of bucket as soon as lambda exceeds 2.0
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}
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return;
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}
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public V get(K key) throws Exception{
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int bi=bucketIndex(key);
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int fountAt=find(bi,key);
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if(fountAt==-1){
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return null;
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}else{
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return buckets[bi].get(fountAt).value;
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}
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}
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public V remove(K key) throws Exception{
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int bi=bucketIndex(key);
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int fountAt=find(bi,key);
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if(fountAt==-1){
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return null;
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}else{
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this.size--;
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return buckets[bi].remove(fountAt).value;
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}
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}
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public boolean containskey(K key) throws Exception{
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int bi=bucketIndex(key);
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int fountAt=find(bi,key);
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if(fountAt==-1){
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return false;
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}else{
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return true;
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}
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}
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public int size(){
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return this.size;
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}
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public boolean isempty(){
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return this.size==0;
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}
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public ArrayList<K> keyset() throws Exception{
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ArrayList<K> arr=new ArrayList<>();
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for(int i=0;i<buckets.length;i++){
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for(int j=0;j<buckets[i].size();j++){
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arr.add(buckets[i].get(j).key);
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}
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}
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return arr;
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}
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public ArrayList<V> valueset() throws Exception{
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ArrayList<V> arr=new ArrayList<>();
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for(int i=0;i<buckets.length;i++){
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for(int j=0;j<buckets[i].size();j++){
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arr.add(buckets[i].get(j).value);
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}
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}
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return arr;
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}
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public void display() throws Exception{
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for(int i=0;i<buckets.length;i++){
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System.out.print("Bucket: "+i+" ");
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for(int j=0;j<buckets[i].size();j++){
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hmnodes temp=buckets[i].get(j);
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System.out.print("["+temp.key+"->"+temp.value+"]");
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}
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System.out.println();
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}
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}
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public int find(int bi,K key) throws Exception{
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for(int i=0;i<buckets[bi].size();i++){
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if(key.equals(buckets[bi].get(i).key))
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return i;
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}
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return -1;
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}
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public int bucketIndex(K key) throws Exception{
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int bi=key.hashCode();
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return Math.abs(bi%buckets.length);
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}
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private void rehash() throws Exception{
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LinkedList<hmnodes> ob[]= buckets;
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buckets=new LinkedList[ob.length*2];
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for(int i=0;i<ob.length*2;i++)
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buckets[i]=new LinkedList<>();
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size = 0;
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for(int i=0;i<ob.length;i++){
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for(int j=0;j<ob[i].size();j++){
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put(ob[i].get(j).key,ob[i].get(j).value);
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}
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}
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}
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}
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>>>>>>> 7e3a8c55c865471a33f6932a022a1059c5243fc3:data_structures/HashMap/HashMap.java
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