Full Stack Interview - FAQ & Answers

1] Arrays 1] Find first and second best score Example Given an array, write a function to get first, second best scores from the array and return it in new array. Array may contain duplicates. Example myArray = { 84 , 85 , 86 , 87 , 85 , 90 , 85 , 83 , 23 , 45 , 84 , 1 , 2 , 0 } firstSecond ( myArray ) // {90, 87} Solution: import java . util . Arrays ; import java . util . Collections ; public class Exercise { public static int [] findTopTwoScores ( int [] array ) { int firstHighest = Integer . MIN_VALUE ; int secondHighest = Integer . MIN_VALUE ;   for ( int score : array ) { if ( score > firstHighest ) { secondHighest = firstHighest ; firstHighest = score ; } else if ( score > secondHighest && score < firstHighest ) { secondHighest = score ; } }   return new int []{ firstHighest , secondHighest }...

The Map data structure in Java is widely used in various scenarios and is a common topic in technical interviews. Here are some examples of how Map can be used in different programs or interview questions, along with Java and Java 8 code snippets. 1. Counting Frequency of Elements Problem: Given an array of integers, count the frequency of each element. Example: import java.util.HashMap; import java.util.Map; public class FrequencyCounter { public static void main (String[] args) { int [] arr = { 1 , 2 , 2 , 3 , 3 , 3 , 4 , 4 , 4 , 4 }; Map<Integer, Integer> frequencyMap = new HashMap <>(); for ( int num : arr) { frequencyMap.put(num, frequencyMap.getOrDefault(num, 0 ) + 1 ); } System.out.println(frequencyMap); } } Output: {1=1, 2=2, 3=3, 4=4} 2. Finding First Non-Repeated Character in a String Problem: Given a string, find the first non-repeated character. Example: import java.util.LinkedHashMa...

In programming, the List data structure is widely used in various scenarios, and interview questions often revolve around its practical applications. Here are some examples of programs where a List is used: 1. Basic Operations on Lists Problem: Implement a program to reverse a list Usage: The list is traversed, and its elements are reordered. Core Java: import java.util.*; public class ReverseList { public static List<Integer> reverseList (List<Integer> list) { Collections.reverse(list); return list; } } Java 8: import java.util.*; import java.util.stream.*; public class ReverseList { public static List<Integer> reverseList (List<Integer> list) { return IntStream.rangeClosed( 1 , list.size()) .mapToObj(i -> list.get(list.size() - i)) .collect(Collectors.toList()); } } Problem: Write a program to remove duplicates from a list. Usage: Lists are used ...