Java interview coding questions - Part 02

Palindrome check

	package com.app.interviews;
	public class PalindromeCheck {
	public static void main(String[] args) {
	int number = 121;
	int sum = 0;
	int r;
	int temp = number;
	while (number != 0) {
	r = number % 10;
	sum = (sum * 10) + r;
	number = number / 10;
	}
	if (temp == sum)
	System.out.println("Palindrome");
	else
	System.out.println("Not a palindrome");
	}
	}

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Reverse a number

	package com.app.interviews;
	public class PalindromeCheck {
	public static void main(String[] args) {
	int number = 121;
	int sum = 0;
	int r;
	int temp = number;
	while (number != 0) {
	r = number % 10;
	sum = (sum * 10) + r;
	number = number / 10;
	}
	if (temp == sum)
	System.out.println("Palindrome");
	else
	System.out.println("Not a palindrome");
	}
	}

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Copy an array

	package interviews;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collections;
	import java.util.List;
	public class CopyArray {
	public static void main(String args[]) {
	int[] a1 = {1, 2, 3};
	int[] a2 = {4, 5, 6};
	int[] a3 = new int[a1.length + a2.length];
	System.arraycopy(a1, 0, a3, 0, a1.length);
	System.arraycopy(a2, 0, a3, a1.length, a2.length);
	System.out.println(Arrays.toString(a3));
	String[] s1 = {"aa", "bb"};
	String[] s2 = {"cc", "ee"};
	List<String> s3 = new ArrayList<>(s1.length + s2.length);
	Collections.addAll(s3, s1);
	Collections.addAll(s3, s2);
	System.out.println(s3);
	}
	}

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Check the longest word

	package com.app.interviews;
	public class LongestWord {
	public static void main(String[] args) {
	String s = "Hi, May I know your name please? ";
	String[] array = s.split(" ");
	String rts = "";
	for (int i = 0; i < array.length; i++) {
	if (array[i].length() > rts.length()) {
	rts = array[i];
	}
	}
	System.out.println(rts);
	// Using foreach
	for (String word : array) {
	if (word.length() > rts.length()) {
	rts = word;
	}
	}
	System.out.println(rts);
	}
	}

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Swap numbers of two integers

	package com.app.interviews;
	public class SwapNumber {
	public static void main(String args[]) {
	int x = 10;
	int y = 20;
	x = x + y;
	y = x - y;
	x = x - y;
	System.out.println(x);
	System.out.println(y);
	}
	}

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Common elements of two arrays

	package com.app.interviews;
	public class CommonElements {
	public static void main(String args[]) {
	int[] a = {1, 2, 3, 4, 5};
	int[] b = {2, 3, 4, 5, 6, 7, 8};
	for (int i = 0; i < a.length; i++) {
	for (int j = 0; j < b.length; j++) {
	if (a[i] == b[j]) {
	System.out.println(a[i]);
	}
	}
	}
	}
	}

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