solved the problem

mock-machine-coding-2.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

src/com/gaurparas/Driver.java

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+package com.gaurparas;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+public class Driver {
+    public static void main(String... args){
+        ExpenseManager expenseManager = new ExpenseManager();
+
+        expenseManager.addUser(new User("u1","User1","paras@gmail.com","+91-00000"));
+        expenseManager.addUser(new User("u2","User2","pushpendra@gmail.com","+91-00001"));
+        expenseManager.addUser(new User("u3","User3","abhinav@gmail.com","+91-00002"));
+        expenseManager.addUser(new User("u4","User4","jancy@gmail.com","+91-00003"));
+
+        Scanner scanner = new Scanner(System.in);
+        while (true) {
+            String command = scanner.nextLine();
+            String[] commands = command.split(" ");
+            String commandType = commands[0];
+
+            switch (commandType){
+                case "SHOW":
+                    if (commands.length == 1) {
+                        expenseManager.showBalances();
+                    } else {
+                        expenseManager.showBalance(commands[1]);
+                    }
+                    break;
+                case "EXPENSE":
+                    String paidBy = commands[1];
+                    Double amount = Double.parseDouble(commands[2]);
+                    int noOfUsers = Integer.parseInt(commands[3]);
+                    String expenseType = commands[4 + noOfUsers];
+                    List<Split> splits = new ArrayList<>();
+                    switch (expenseType){
+                        case "EXACT":
+                            for(int i=0;i<noOfUsers;i++){
+                                splits.add(new ExactSplit(expenseManager.userMap.get(commands[4+i]),
+                                        Double.parseDouble(commands[5+noOfUsers+i])));
+                            }
+                            expenseManager.addExpense(ExpenseType.EXACT, amount, paidBy, splits, null);
+                            break;
+                        case "EQUAL":
+                            for(int i=0;i<noOfUsers;i++){
+                                splits.add(new EqualSplit(expenseManager.userMap.get(commands[4+i])));
+                            }
+                            expenseManager.addExpense(ExpenseType.EQUAL, amount, paidBy, splits, null);
+                            break;
+                        case "PERCENT":
+                            for (int i = 0; i < noOfUsers; i++) {
+                                splits.add(new PercentSplit(expenseManager.userMap.get(commands[4 + i]), Double.parseDouble(commands[5 + noOfUsers + i])));
+                            }
+                            expenseManager.addExpense(ExpenseType.PERCENT, amount, paidBy, splits, null);
+                            break;
+                    }
+                    break;
+            }
+        }
+    }
+}

src/com/gaurparas/EqualExpense.java

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+package com.gaurparas;
+
+import java.util.List;
+
+public class EqualExpense extends Expense{
+
+    public EqualExpense(double amount, User paidBy, List<Split> splits, ExpenseMetaData metaData) {
+        super(amount, paidBy, splits, metaData);
+    }
+
+    @Override
+    public boolean validate() {
+        List<Split> splits = getSplits();
+
+        for(Split split:splits) {
+            if (!(split instanceof EqualSplit)){
+                return false;
+            }
+        }
+
+        return true;
+    }
+}

src/com/gaurparas/EqualSplit.java

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+package com.gaurparas;
+
+public class EqualSplit extends Split {
+
+    public EqualSplit(User user) {
+        super(user);
+    }
+}

src/com/gaurparas/ExactExpense.java

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+package com.gaurparas;
+
+import java.util.List;
+
+public class ExactExpense extends Expense {
+
+    public ExactExpense(double amount, User paidBy, List<Split> splits, ExpenseMetaData metaData) {
+        super(amount, paidBy, splits, metaData);
+    }
+
+    @Override
+    public boolean validate() {
+        List<Split> splits = getSplits();
+        double splitsAmount = 0;
+
+        for(Split split:splits) {
+            if (!(split instanceof EqualSplit)){
+                return false;
+            }
+            splitsAmount+=split.getAmount();
+        }
+
+        return splitsAmount == getAmount();
+    }
+}

src/com/gaurparas/ExactSplit.java

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+package com.gaurparas;
+
+public class ExactSplit extends Split {
+
+    public ExactSplit(User user, double amount) {
+        super(user);
+        this.amount = amount;
+    }
+}

src/com/gaurparas/Expense.java

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+package com.gaurparas;
+
+import java.util.List;
+
+public abstract class Expense {
+    private String id;
+    private List<Split> splits;
+    private User paidBy;
+    private double amount;
+    private ExpenseMetaData metaData;
+
+    public Expense(double amount, User paidBy, List<Split> splits, ExpenseMetaData metaData) {
+        this.amount = amount;
+        this.paidBy = paidBy;
+        this.splits = splits;
+        this.metaData = metaData;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public double getAmount() {
+        return amount;
+    }
+
+    public void setAmount(double amount) {
+        this.amount = amount;
+    }
+
+    public User getPaidBy() {
+        return paidBy;
+    }
+
+    public void setPaidBy(User paidBy) {
+        this.paidBy = paidBy;
+    }
+
+    public List<Split> getSplits() {
+        return splits;
+    }
+
+    public void setSplits(List<Split> splits) {
+        this.splits = splits;
+    }
+
+    public ExpenseMetaData getMetadata() {
+        return metaData;
+    }
+
+    public void setMetadata(ExpenseMetaData metaData) {
+        this.metaData = metaData;
+    }
+
+    public abstract boolean validate();
+}

src/com/gaurparas/ExpenseManager.java

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+package com.gaurparas;
+
+import com.sun.deploy.cache.BaseLocalApplicationProperties;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class ExpenseManager {
+
+    List<Expense> expenses;
+    Map<String, User> userMap;
+    Map<String, Map<String, Double>> balanceSheet;
+
+    public ExpenseManager() {
+        expenses = new ArrayList<Expense>();
+        userMap = new HashMap<String, User>();
+        balanceSheet = new HashMap<String, Map<String, Double>>();
+    }
+
+    public void addUser(User user) {
+        userMap.put(user.getId(), user);
+        balanceSheet.put(user.getId(), new HashMap<String, Double>());
+    }
+
+    public void showBalances() {
+        boolean isEmpty = true;
+        for(Map.Entry<String, Map<String, Double>> allBalance : balanceSheet.entrySet()) {
+            for (Map.Entry<String, Double> userBalance : allBalance.getValue().entrySet()) {
+                if (userBalance.getValue() > 0) {
+                    isEmpty = false;
+                    printBalance(allBalance.getKey(), userBalance.getKey(), userBalance.getValue());
+                }
+            }
+        }
+        if (isEmpty) {
+            System.out.println("No balances");
+        }
+    }
+
+    public void showBalance(String userId) {
+        boolean isEmpty = true;
+        for(Map.Entry<String, Double> userBalance : balanceSheet.get(userId).entrySet()) {
+            if(userBalance.getValue() != 0){
+                isEmpty = false;
+                printBalance(userId, userBalance.getKey(), userBalance.getValue());
+            }
+        }
+        if (isEmpty) {
+            System.out.println("No balances");
+        }
+    }
+
+    private void printBalance(String user1, String user2, Double amount) {
+        String user1Name = userMap.get(user1).getName();
+        String user2Name = userMap.get(user2).getName();
+        if (amount < 0) {
+            System.out.println(user1Name + " owes " + user2Name + ": " + Math.abs(amount));
+        } else if (amount > 0) {
+            System.out.println(user2Name + " owes " + user1Name + ": " + Math.abs(amount));
+        }
+    }
+
+    public void addExpense(ExpenseType expenseType, Double amount, String paidBy,
+                           List<Split> splits, ExpenseMetaData metaData) {
+        Expense expense = ExpenseService.createExpense(expenseType, amount, userMap.get(paidBy),
+                splits, metaData);
+        expenses.add(expense);
+
+        Map<String, Double> userBalances = balanceSheet.get(paidBy);
+        for(Split split:splits) {
+            String oweUser = split.getUser().getId();
+            double prevAmount = userBalances.getOrDefault(oweUser,0.0);
+            double currentAmount = split.getAmount();
+            userBalances.put(oweUser,prevAmount + currentAmount);
+
+            Map<String, Double> OweUserBalances = balanceSheet.get(oweUser);
+            prevAmount = OweUserBalances.getOrDefault(paidBy,0.0);
+            OweUserBalances.put(paidBy,prevAmount - currentAmount);
+        }
+    }
+}

src/com/gaurparas/ExpenseMetaData.java

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+package com.gaurparas;
+
+public class ExpenseMetaData {
+    private String name;
+    private String imgUrl;
+    private String notes;
+
+    public ExpenseMetaData(String name, String imgUrl, String notes) {
+        this.name = name;
+        this.imgUrl = imgUrl;
+        this.notes = notes;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getImgUrl() {
+        return imgUrl;
+    }
+
+    public void setImgUrl(String imgUrl) {
+        this.imgUrl = imgUrl;
+    }
+
+    public String getNotes() {
+        return notes;
+    }
+
+    public void setNotes(String notes) {
+        this.notes = notes;
+    }
+}

src/com/gaurparas/ExpenseService.java

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+package com.gaurparas;
+
+import java.util.List;
+
+public class ExpenseService {
+    public static Expense createExpense(ExpenseType expenseType, double amount, User paidBy,
+                                        List<Split> splits, ExpenseMetaData metaData) {
+        switch (expenseType) {
+            case EXACT:
+                return new ExactExpense(amount, paidBy, splits, metaData);
+            case EQUAL:
+                int totalSplits = splits.size();
+                double splitAmount = ((double) Math.round(amount*100/totalSplits))/100.0;
+                for(Split split:splits){
+                    split.setAmount(splitAmount);
+                }
+                splits.get(0).setAmount(splitAmount + (amount-splitAmount*totalSplits));
+                return new EqualExpense(amount, paidBy, splits, metaData);
+            case PERCENT:
+                for(Split split:splits){
+                    double percentSplit = ((PercentSplit)split).getPercent();
+                    split.setAmount(amount*percentSplit/100);
+                }
+                return new PercentExpense(amount, paidBy, splits, metaData);
+            default:
+                return null;
+        }
+    }
+}