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Ravi Yasas
Ravi Yasas

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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");
}
}

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");
}
}

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);
}
}
view raw CopyArray.java hosted with ❤ by GitHub

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);
}
}

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);
}
}
view raw SwapNumber.java hosted with ❤ by GitHub

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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