Programming Challenges and Solutions

FizzBuzz

        
           public class FizzBuzz {
    public static void main(String[] args) {
        for (int i = 1; i <= 100; i++) {
            if (i % 3 == 0 && i % 5 == 0) {
                System.out.println("FizzBuzz");
            } else if (i % 3 == 0) {
                System.out.println("Fizz");
            } else if (i % 5 == 0) {
                System.out.println("Buzz");
            } else {
                System.out.println(i);
            }
        }
    }
}

        
    

Factorial

        
          public class Factorial {
    public static int calculateFactorial(int n) {
        if (n == 0 || n == 1) {
            return 1;
        } else {
            return n * calculateFactorial(n - 1);
        }
    }
    
    public static void main(String[] args) {
        int number = 5; // Replace with the desired number
        int factorial = calculateFactorial(number);
        System.out.println("Factorial of " + number + " is: " + factorial);
    }
}

        
    

Fibonacci Sequence

        
         public class Fibonacci {
    public static void generateFibonacci(int n) {
        int a = 0, b = 1;
        System.out.print("Fibonacci Sequence (" + n + " terms): ");
        
        for (int i = 1; i <= n; i++) {
            System.out.print(a + " ");
            int sum = a + b;
            a = b;
            b = sum;
        }
    }
    
    public static void main(String[] args) {
        int terms = 10; // Replace with the desired number of terms
        generateFibonacci(terms);
    }
}

        
    

Palindrome Checker

        
          public class Palindrome {
    public static boolean isPalindrome(String str) {
        str = str.replaceAll("[^a-zA-Z0-9]", "").toLowerCase();
        int left = 0;
        int right = str.length() - 1;
        
        while (left < right) {
            if (str.charAt(left) != str.charAt(right)) {
                return false;
            }
            left++;
            right--;
        }
        return true;
    }
    
    public static void main(String[] args) {
        String input = "A man, a plan, a canal, Panama!";
        boolean result = isPalindrome(input);
        System.out.println("Is palindrome: " + result);
    }
}

        
    

Prime Number Generator

        
         public class PrimeNumberGenerator {
    public static boolean isPrime(int num) {
        if (num <= 1) {
            return false;
        }
        
        for (int i = 2; i <= Math.sqrt(num); i++) {
            if (num % i == 0) {
                return false;
            }
        }
        return true;
    }
    
    public static void generatePrimes(int limit) {
        System.out.println("Prime numbers up to " + limit + ":");
        for (int i = 2; i <= limit; i++) {
            if (isPrime(i)) {
                System.out.print(i + " ");
            }
        }
    }
    
    public static void main(String[] args) {
        int limit = 50; // Replace with the desired limit
        generatePrimes(limit);
    }
}

        
    

String Reversal

        
           public class StringReversal {
    public static String reverseString(String str) {
        StringBuilder reversed = new StringBuilder();
        for (int i = str.length() - 1; i >= 0; i--) {
            reversed.append(str.charAt(i));
        }
        return reversed.toString();
    }
    
    public static void main(String[] args) {
        String input = "Hello, World!";
        String reversed = reverseString(input);
        System.out.println("Reversed string: " + reversed);
    }
}

        
    

Count Characters

        
          public class CharacterCounter {
    public static void countCharacters(String str) {
        int[] counts = new int[256]; // Assuming ASCII characters
        
        for (char c : str.toCharArray()) {
            counts[c]++;
        }
        
        for (int i = 0; i < 256; i++) {
            if (counts[i] > 0) {
                System.out.println((char) i + ": " + counts[i]);
            }
        }
    }
    
    public static void main(String[] args) {
        String input = "programming";
        countCharacters(input);
    }
}

        
    

Anagram Checker

        
           public class AnagramChecker {
    public static boolean areAnagrams(String str1, String str2) {
        if (str1.length() != str2.length()) {
            return false;
        }
        
        int[] counts = new int[256]; // Assuming ASCII characters
        
        for (char c : str1.toCharArray()) {
            counts[c]++;
        }
        
        for (char c : str2.toCharArray()) {
            if (counts[c] == 0) {
                return false;
            }
            counts[c]--;
        }
        
        return true;
    }
    
    public static void main(String[] args) {
        String str1 = "listen";
        String str2 = "silent";
        boolean result = areAnagrams(str1, str2);
        System.out.println("Are anagrams: " + result);
    }
}

        
    

        
         public class LargestSmallest {
    public static void findLargestSmallest(int[] arr) {
        if (arr.length == 0) {
            System.out.println("Array is empty.");
            return;
        }
        
        int smallest = arr[0];
        int largest = arr[0];
        
        for (int num : arr) {
            if (num < smallest) {
                smallest = num;
            }
            if (num > largest) {
                largest = num;
            }
        }
        
        System.out.println("Smallest: " + smallest);
        System.out.println("Largest: " + largest);
    }
    
    public static void main(String[] args) {
        int[] numbers = {10, 5, 23, 87, 2, 45};
        findLargestSmallest(numbers);
    }
}

        
    

        
          public class BinaryToDecimal {
    public static int binaryToDecimal(String binary) {
        int decimal = 0;
        int power = 0;
        
        for (int i = binary.length() - 1; i >= 0; i--) {
            if (binary.charAt(i) == '1') {
                decimal += Math.pow(2, power);
            }
            power++;
        }
        
        return decimal;
    }
    
    public static void main(String[] args) {
        String binary = "110110";
        int decimal = binaryToDecimal(binary);
        System.out.println("Binary " + binary + " is decimal " + decimal);
    }
}