// Interview Coding Exercises // 1. CLASSIC: Write a bulkified trigger // Prompt: "Write a trigger that updates the Account's total revenue // when Opportunities are inserted or updated." trigger OpportunityTrigger on Opportunity (after insert, after update) { // Collect affected Account IDs Set accountIds = new Set(); for (Opportunity opp : Trigger.new) { if (opp.AccountId != null) { accountIds.add(opp.AccountId); } } // Also check old values for reparented opps if (Trigger.isUpdate) { for (Opportunity opp : Trigger.old) { if (opp.AccountId != null) { accountIds.add(opp.AccountId); } } } if (accountIds.isEmpty()) return; // Aggregate opportunity amounts per account Map revenueByAccount = new Map(); for (AggregateResult ar : [ SELECT AccountId, SUM(Amount) totalAmount FROM Opportunity WHERE AccountId IN :accountIds AND StageName = 'Closed Won' GROUP BY AccountId ]) { revenueByAccount.put( (Id) ar.get('AccountId'), (Decimal) ar.get('totalAmount') ); } // Update accounts List accountsToUpdate = new List(); for (Id accId : accountIds) { accountsToUpdate.add(new Account( Id = accId, Total_Revenue__c = revenueByAccount.containsKey(accId) ? revenueByAccount.get(accId) : 0 )); } update accountsToUpdate; } // 2. CODE REVIEW: Find and fix all issues in this code // Prompt: "Review this code and identify all problems" /* BUGGY CODE (find the issues): trigger CaseTrigger on Case (after insert) { for (Case c : Trigger.new) { Account acc = [SELECT Id, Name FROM Account WHERE Id = :c.AccountId]; c.Description = 'Account: ' + acc.Name; update c; EmailService.sendEmail(c.ContactEmail, 'Case Created', c.Subject); Task t = new Task(); t.WhatId = c.Id; t.Subject = 'Follow up'; insert t; } } ISSUES: 1. SOQL inside loop — will fail at 101 records 2. DML inside loop (update c) — will fail at 151 records 3. Cannot modify Trigger.new in after trigger (read-only) 4. DML inside loop (insert t) — another DML per iteration 5. Email in loop — will hit email invocation limit 6. No null check on AccountId 7. No error handling 8. Single trigger, should use handler pattern */ // FIXED VERSION: public class CaseTriggerHandler { public static void handleAfterInsert(List cases) { // Collect data Set accountIds = new Set(); for (Case c : cases) { if (c.AccountId != null) accountIds.add(c.AccountId); } // Query once Map accounts = new Map( [SELECT Id, Name FROM Account WHERE Id IN :accountIds] ); // Process List casesToUpdate = new List(); List tasksToCreate = new List(); List emails = new List(); for (Case c : cases) { // Update case description Account acc = accounts.get(c.AccountId); if (acc != null) { casesToUpdate.add(new Case( Id = c.Id, Description = 'Account: ' + acc.Name )); } // Create follow-up task tasksToCreate.add(new Task( WhatId = c.Id, Subject = 'Follow up on case: ' + c.CaseNumber, ActivityDate = Date.today().addDays(1) )); } // DML once each if (!casesToUpdate.isEmpty()) update casesToUpdate; if (!tasksToCreate.isEmpty()) insert tasksToCreate; } } // 3. SYSTEM DESIGN: Design a Lead scoring system // Prompt: "Design a system that scores Leads based on behavior and demographics" public class LeadScoringEngine { // Configuration-driven scoring via Custom Metadata public static void scoreLeads(List leads) { // Load scoring rules from Custom Metadata List rules = [ SELECT Category__c, Field_Name__c, Operator__c, Value__c, Points__c FROM Lead_Score_Rule__mdt WHERE Is_Active__c = true ]; for (Lead lead : leads) { Integer score = 0; for (Lead_Score_Rule__mdt rule : rules) { if (evaluateRule(lead, rule)) { score += (Integer) rule.Points__c; } } lead.Lead_Score__c = score; lead.Score_Grade__c = getGrade(score); } } private static Boolean evaluateRule(Lead lead, Lead_Score_Rule__mdt rule) { Object fieldValue = lead.get(rule.Field_Name__c); if (fieldValue == null) return false; String valueStr = String.valueOf(fieldValue); switch on rule.Operator__c { when 'equals' { return valueStr == rule.Value__c; } when 'contains' { return valueStr.contains(rule.Value__c); } when 'not_empty' { return String.isNotBlank(valueStr); } when else { return false; } } } private static String getGrade(Integer score) { if (score >= 80) return 'A'; if (score >= 60) return 'B'; if (score >= 40) return 'C'; if (score >= 20) return 'D'; return 'F'; } }

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