1. Consider the following Transaction class: package com.personetics.entities; import java.util.Date; public class Transaction { String id; String accountId; Double amount; Date date; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getAccountId() { return accountId; } public void setAccountId(String accountId) { this.accountId = accountId; } public Double getAmount() { return amount; } public void setAmount(Double amount) { this.amount = amount; } public Date getDate() { return date; } public void setDate(Date date) { this.date = date; } } Design a data structure that gets as input a collection of Transaction objects from the last 6 months and supports the following methods in runtime complexity of O(1): ? insert(Transaction transaction) ? Double getAvg() ? Returns the average amount of all transactions. ? List getTransactionsOfMonthForAccount(int month, String accountI
