Introduction
Table of Contents
Top Easy Interview Coding Programs
Reverse String
private static void reverseString() {
String reverse = "abcd";
StringBuilder builder = new StringBuilder(reverse);
builder = builder.reverse();
System.out.println(builder);
}
Reverse String Without In buildAPI
private static void reverseStringWithoutInbuildAPI() {
String reverse = "abcd";
char[] array = reverse.toCharArray();
for (int i = array.length -1; i >= 0; i--) {
System.out.print(array[i]);
}
}
Swap Without Third Variable
private static void swapTwoNumbersWithoutVariable() {
int x =10;
int y = 2;
x = x + y;
y = x - y;
x = x - y;
System.out.println(" x=" + x + ",y=" + y);
}
Find Repeating Words in a Sentence
private static void findRepeatingWords() {
String repeatingString = "next time there won't be a next time";
String[] str = repeatingString.split(" ");
HashMap<String, Integer> hashMap = new HashMap<>();
for (int i = 0; i < str.length; i++) {
if (hashMap.containsKey(str[i])) {
int count = hashMap.get(str[i]);
hashMap.put(str[i], count + 1);
} else {
hashMap.put(str[i], 1);
}
}
System.out.println(hashMap);
}
Check Prime Number
private static void checkPrimeNumber() {
boolean prime = true;
int number = 30;
for (int i=2; i <= number / 2 ; i++) {
int rem = number % i;
if (rem == 0) {
prime = false;
break;
}
}
System.out.println(prime);
}
Check Fibonacci Number
private static void checkFibonacciNumber() {
int number = 20;
int a = 0, b = 0, c = 1;
for (int i = 0; i < number; i++) {
a = b;
b = c;
c = a + b;
System.out.println(a);
}
}
Check Armstrong Number
private static void checkArmstrongNumber() {
int number = 153;
int temp = number;
int sum = 0;
while (number > 0) {
int rem = number % 10;
number = number / 10;
sum = sum + (rem * rem * rem);
}
if (sum == temp) {
System.out.println("Armstrong");
} else {
System.out.println("Not Armstrong");
}
}
Check Palindrome Number
private static void checkPalindromeNumber() {
int number = 1221;
int temp = number;
int sum = 0;
while (number > 0) {
int rem = number % 10;
number = number / 10;
sum = sum * 10 + rem;
}
if (sum == temp) {
System.out.println("Palindrome");
} else {
System.out.println(" Not Palindrome");
}
}
Check Anagram String
private static void checkAnagramNumber() {
String string1 = "listen";
String string2 = "silent";
char[] charArray1 = string1.toCharArray();
char[] charArray2 = string2.toCharArray();
Arrays.sort(charArray1);
Arrays.sort(charArray2);
System.out.println(Arrays.equals(charArray1, charArray2));
}
Generate Factorial Number
private static int generateFactorialNumber(int number) {
if (number == 1) {
return number;
}
return number * generateFactorialNumber(number - 1);
}
Print Triangle
private static void printTriangle() {
for (int i = 0; i < 5; i++) {
for (int k = 0; k < 5 - i; k++) {
System.out.print(" ");
}
for (int j = 0; j <= i; j++) {
System.out.print("* ");
}
System.out.println();
}
}
Selection Sort
private static void selectionSort() {
int[] numberArray = { 4, 6, 2, 8, 22, 34, 12 };
ArrayList<Integer> intList = IntStream.of(numberArray).boxed().collect(Collectors.toCollection(ArrayList::new));
for (int i = 0; i < intList.size(); i++) {
for (int j = i + 1; j < intList.size(); j++) {
if (intList.get(i) > intList.get(j)) {
int temp = intList.get(i);
intList.set(i, intList.get(j));
intList.set(j, temp);
}
}
}
intList.stream().forEach(System.out::println);
}
