rohanjai777

public class Solution {
    public int solve(int A, int[][] B) {
        ArrayList<Integer>[] graph = new ArrayList[A+1]; //A+1 because vertex are from 1 to A
        for(int i=0;i<=A;i++){ //make graph
            graph[i] = new ArrayList<>();
        }
        for(int i=0;i<B.length;i++){
            int v1 = B[i][0];
            int v2 = B[i][1];
            graph[v1].add(v2);

rohanjai777

class Student{
    private String name;
    private String phone;
    private String age;
    
    public static StudentBuilder getStudentBuilder(){ //to return StudentBuilder object 
        return new StudentBuilder();
    }
    
    public void print(){

rohanjai777

class DBC{
    static int a = 10;
    private static DBC dbc;
    private DBC(){}
    public static DBC getInstance(){ //not thread safe
        if(dbc == null){
            dbc = new DBC();
        }
        return dbc;
    }

rohanjai777

import java.util.*;

class Player{
    String name;
    int currentPosition;
    Player(String name, int currentPosition){
        this.name = name;
        this.currentPosition = currentPosition;
    }
}

rohanjai777

import java.util.*;
enum TransportMode{
    CAR,
    BIKE,
    WALK
}
//-----------------------------------------
interface PathStrategy{
    public void calculatePath(String from, String to);
}

rohanjai777

import java.util.*;
interface PaymentSuccessEventSubscriber{//has common method called notify
    void notify(int order_id);
}

class EmailService implements PaymentSuccessEventSubscriber{ 
    public void notify(int order_id){
        sendEmail(order_id);
    }
    public void sendEmail(int order_id){

rohanjai777

interface Icecream{
   int getPrice();
   void printComposition();
}

class ChocoWafer implements Icecream{ //make a ChocoWafer class
    private Icecream icecream; //already made cone if any
    private int price = 20; 
    
    ChocoWafer(){} //if no cone till now

rohanjai777

import java.util.*;

enum BulletType { //type of bullets available
    FIVE_MM,
    SEVEN_MM,
    NINE_MM,
}
//-------------
class Bullet{ //intrinsic properties
    int weight;

rohanjai777

interface PaymentApi{ //Iterface for payments apis 
    boolean startTransaction(int transactionId);
    boolean checkCompletion(int transactionId);
}

//---------------------
//Make individual adapters to connect 
class PayUAdapter implements PaymentApi{ //Adapter to connect
    PayUApi api = new PayUApi();
    

rohanjai777

import java.util.*;

enum PageType{
    A4,
    A3,
    A5
}
//----------------------------
class NoteBook{
    private PageType pageType; //attributes