Core Java Programs Archives

Write a Program to find the second largest number in array in Java

April 1, 2022

2 min read

Hey guys in this article, we will discuss finding the second largest number in array using Java. First, let’s look at the solution then I will explain the solution. Watch the Video Solution public class...

Counting Sort Java Program Logic

September 27, 2021

by Bushan Sirgur

2 min read

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Hey guys in this post, we will discuss the most popular sorting algorithm that is Counting sort in Java language. Read more: Check the Complete Java Tutorials Check the Complete Spring Boot Tutorials [100+ Examples] Check the...

Heap Sort Java Program Logic

September 27, 2021

by Bushan Sirgur

2 min read

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Hey guys in this post, we will discuss the most popular sorting algorithm that is Heap sort in Java language. Read more: Check the Complete Java Tutorials Check the Complete Spring Boot Tutorials [100+ Examples] Check the...

Selection Sort Java Program Logic

September 27, 2021

by Bushan Sirgur

2 min read

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Hey guys in this post, we will discuss the most popular sorting algorithm that is Selection sort in Java language. Read more: Check the Complete Java Tutorials Check the Complete Spring Boot Tutorials [100+ Examples] Check the...

Quick Sort Java Program Logic

September 27, 2021

by Bushan Sirgur

2 min read

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Hey guys in this post, we will discuss the most popular sorting algorithm that is Quick sort in Java language. Read more: Check the Complete Java Tutorials Check the Complete Spring Boot Tutorials [100+ Examples] Check the...

Radix Sort Java Program Logic

September 27, 2021

by Bushan Sirgur

3 min read

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Hey guys in this post, we will discuss the most popular sorting algorithm that is Radix sort in Java language. Read more: Check the Complete Java Tutorials Check the Complete Spring Boot Tutorials [100+ Examples] Check the...

Merge Sort Java Program Logic

September 27, 2021

by Bushan Sirgur

3 min read

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Hey guys in this post, we will discuss the most popular sorting algorithm that is Merge sort in Java language. Read more: Check the Complete Java Tutorials Check the Complete Spring Boot Tutorials [100+ Examples] Check the...

Insertion Sort Java Program Logic

September 27, 2021

by Bushan Sirgur

2 min read

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Hey guys in this post, we will discuss the most popular sorting algorithm that is Insertion sort in Java language. Read more: Check the Complete Java Tutorials Check the Complete Spring Boot Tutorials [100+ Examples] Check the...

Given an array of ints, return true if the value 3 appears in the array exactly 3 times, and no 3’s are next to each other.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status haveThree({12,3,4,3,88,3}) true OK haveThree({22,3,3,3,17,3}) false OK haveThree({3,4,3,6,3,7}) true OK Java solution package test; public class Program20...

Given an array of ints, return true if the sum of all the 2’s in the array is exactly 8.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status sum28({10,20,30,40,50,60,2}) false OK sum28({2,10,7,2,2,2}) true OK sum28({5,6,1,2,2,2}) false OK Java solution package test; public class Program19 { public...

Given a string and an int n, return a string made of the first and last ‘ n’ chars from the string. The string length will be at least n.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status nTwice(Hello,2) Helo OK nTwice(Chocolate,3) Choate OK nTwice(java,1) ja OK Java solution package test; public class Program18 { public static void...

Given an “out” string length 4, such as “<<>>”, and a word, return a new string where the word is in the middle of the out string, e.g. “<>”

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status makeOutWord(<<>>,Yay) <<Yay>> OK makeOutWord([[]],Word) [[Word]] OK makeOutWord([((JAVA))] ((JAVA)) OK Java solution package...

Return true if the given string contains 1 or 3 ‘e’ chars. Otherwise return false.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status stringE(Hello) true OK stringE(Heelele) false OK stringE(Heelle) true OK Java solution package test; public class Program16 { public static void...

Return true if the array contains, somewhere, three increasing adjacent numbers like …. 4, 5, 6, … or 23, 24, 25.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status tripleUp({1,2,3,7,5,9}) true OK tripleUp({1,4,5,6,2}) true OK tripleUp({1,2,4,5}) false OK Java solution package test; public class Program15 { public static...

Pass an int as parameter. Find the sum of the digits in the number and return it.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status sumOfDigits(144) 9 OK sumOfDigits(457) 16 OK sumOfDigits(345) 12 OK Java solution package test; public class Program14 { public static void main(String[]...

Given a string of even length, return the first half. So the string “WooHoo” yields “Woo”.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status firstHalf(HelloThere) Hello OK firstHalf(abcdef) abc OK firstHalf(Word) Wo OK Java solution package test; public class Program13 { public static void...

Given an array of ints, return true if one of the first 4 elements in the array is a 9. The array length will be greater than 4.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status arrayFront9({1,2,9,3,4}) true OK arrayFront9({9,2,3,4,56}) true OK arrayFront9({2,3,4,5}) false OK Java solution package test; public class Program12...

Write a program to generate Fibonacci series of limit number of elements.

February 2, 2021

by Bushan Sirgur

1 min read

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Following are the test cases Test cases Result Status generateFibSeries(5) {0,1,1,2,3} Ok generateFibSeries(7) {0,1,1,2,3,5,8} Ok generateFibSeries(10) {0,1,1,2,3,5,8,13,21,34} Ok Java solution public class Program11...

Given a string, return a new string where the first and last chars have been exchanged

January 5, 2021

by Bushan Sirgur

1 min read

2 Comments

Test cases Test cases Expected Result frontBack(abcd) dbca OK frontBack(Bee) eeB OK frontBack(MazE) EazM OK Java solution: public class Program10 { public static void main(String[] args)...

Pass an int array and an int and do a search of the second parameter in the first, and return true/false.

January 5, 2021

by Bushan Sirgur

1 min read

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Test cases Test cases Expected Result searchElement({33,44,21,98,27,94},21) true OK searchElement({1232,432,546,980,984},980) true OK searchElement({3,4,9,87,29},2) false OK Java solution: public class Program9...

Given an array of ‘N’ elements .Return the sum of all array elements

January 5, 2021

by Bushan Sirgur

1 min read

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Test cases Test cases Expected Result arraySum({5,5,5,5,5}) 25 OK arraySum({1,3,4,7,8}) 23 OK arraySum({100,200,300}) 600 OK Java solution: public class Program8 { public static void main(String[] args) { int a[]...

Accept a string as parameter. Find out how many consonants present in it.

December 29, 2020

by Bushan Sirgur

1 min read

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Test cases: Test cases Expected Result countConsonents(instanceof is for references only) –>[18] 18 OK countConsonents(Object Oriented) –>[8] 8 OK countConsonents(Design Patterns88)...

Pass a string as parameter. Find out how many vowels present in it

December 29, 2020

by Bushan Sirgur

1 min read

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Test cases: Test cases Expected Result countVowels(instanceif is for references only) 11 OK countVowels(Object Oriented) 6 OK countVowels(Design Patterns) 4 OK Java solution: public class Program6 { public static...

Given two strings, append them together (known as “concatenation”) and return the result.

December 29, 2020

by Bushan Sirgur

1 min read

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Test cases: Test cases Expected Result stringConcat(Hello,World) Hello World OK stringConcat(Code,ranch) Code ranch OK stringConcat(Web,Application) Web Application OK Java solution: public class Program5 { public...

Return true if the given non-negative number is a multiple of 3 or a multiple of 5

December 29, 2020

by Bushan Sirgur

1 min read

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Test cases: Test cases Expected Result or35(15) true OK or35(8) false OK or35(12) true OK Java solution: public class Program4 { public static void main(String[] args)...

Test whether the number is divisible by 7 or not

December 29, 2020

by Bushan Sirgur

1 min read

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Test cases: Test cases Expected Result isDivisibleBy7(17) false OK isDivisibleBy7(77) true OK isDivisibleBy7(12) false OK Java solution: public class Program3 { public static void main(String[] args)...

Check the given number is odd or even

December 29, 2020

by Bushan Sirgur

1 min read

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Test cases: Test cases Expected Result testOddEven(12) even OK testOddEven(3) odd OK testOddEven(-55) odd OK Java solution: package test; public class Program2 { public static void main(String[] args)...

Pass two ints as parameter and return the sum of numbers.

December 29, 2020

by Bushan Sirgur

1 min read

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Test cases: Test cases Expected Result sum(10,12) 22 OK sum(1,2) 3 OK sum(2147483647,1) 2147483648 OK Java solution: public class Sum { public static void main(String[] args) { Sum.sum(10, 12); Sum.sum(1...

Interview Program – Matrix

January 12, 2020

by Bushan Sirgur

1 min read

1 Comment

Print matrix in Z form. Input: mat[][] = {1, 2, 3, 4, 5, 6, 7, 8, 9} Output: 1 2 3 5 7 8 9 public class PrintTheMatrixOrder { public static void printTheMatrix(int mat[][]) { for (int i = 0; i < mat.length; i++)...

Interview Program

January 12, 2020

by Bushan Sirgur

1 min read

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Print all jumping numbers smaller than or equal to x. Input: x = 105 Output: 0 1 2 3 4 5 6 7 8 9 10 12 21 23 32 34 43 45 54 56 65 67 76 78 87 89 98 101 Note: A number is called as a jumping number if all adjacent digits in it...