Coderbyte Algorithms

01) Coderbyte

Coderbyte Questions and Answers

02) first_factorial_subject

First Factorial
Have the function FirstFactorial(num) take the num parameter being passed and return the factorial of it. For example: if num = 4, then your program should return (4 * 3 * 2 * 1) = 24. For the test cases, the range will be between 1 and 18 and the input will always be an integer.
Examples
Input: 4
Output: 24

03) first_factorial.java

import java.util.*; 
import java.io.*;

10/10

class Main {

  public static int FirstFactorial(int num) {
    
    int result;
    result = 1;

    while (num >= 1)
    { 
      result = result * num; 
      num--;
    }

    return result;
  }

  public static void main (String[] args) {  
    // keep this function call here     
    Scanner s = new Scanner(System.in);
    System.out.print(FirstFactorial(s.nextLine())); 
  }

}

04) first_reverse_subject

First Reverse
Have the function FirstReverse(str) take the str parameter being passed and return the string in reversed order. For example: if the input string is "Hello World and Coders" then your program should return the string sredoC dna dlroW olleH.
Examples
Input: "coderbyte"
Output: etybredoc
Input: "I Love Code"
Output: edoC evoL I

05) first_reverse.java

// LONG SOLUTION (BASED ECOLE 42)
// ******************************

import java.util.*; 
import java.io.*;

class Main {

  public static String FirstReverse(String str) {
    char[] charArray = str.toCharArray();
    char[] reversedArray = new char[charArray.length];
    
    int i = charArray.length - 1;
    int j = 0;

    while (i >= 0) {
      reversedArray[j] = charArray[i];
      i--;
      j++;
    }
    
    String reversedStr = new String(reversedArray);
    return reversedStr;
  }

  public static void main(String[] args) {  
    Scanner s = new Scanner(System.in);
    System.out.print(FirstReverse(s.nextLine())); 
  }

}

// SHORT SOLUTION
// **************

10/10

import java.util.*; 
import java.io.*;

class Main {
  public static String FirstReverse(String str) {
  
    StringBuilder builder_str = new StringBuilder(str);
    String reversed_str = builder_str.reverse().toString();
    return reversed_str; 
    // or make in one line ;
    // return new StringBuilder(str).reverse().toString()
  
  }

  public static void main (String[] args) {  
    // keep this function call here     
    Scanner s = new Scanner(System.in);
    System.out.print(FirstReverse(s.nextLine())); 
  }

}

06) longest_word_subject

Longest Word
Have the function LongestWord(sen) take the sen parameter being passed and return the longest word in the string. If there are two or more words that are the same length, return the first word from the string with that length. Ignore punctuation and assume sen will not be empty. Words may also contain numbers, for example "Hello world123 567"
Examples
Input: "fun&!! time"
Output: time
Input: "I love dogs"
Output: love

07 ) longest_word.java

import java.util.*; 
import java.io.*;

10/10

class Main {

public static String LongestWord(String sen) {
  
    // input => "fun123&!! time"
    String sen_replaced = sen.replaceAll("[^a-zA-Z0-9 ]", ""); // "fun123 time"
    String[] words = sen_replaced.split(" "); // {"fun123","time"}
    
    String longestWord = ""; // define ="" for wont take error NullPointerException
    
    for (String word : words) {
        if (word.length() > longestWord.length()) {
            longestWord = word;  // fun123
        }
    }
    return longestWord;
}

  public static void main (String[] args) {  
    // keep this function call here     
    Scanner s = new Scanner(System.in);
    System.out.print(LongestWord(s.nextLine())); 
  }

}

08) questions_marks

Questions Marks
Have the function QuestionsMarks(str) take the str string parameter, which will contain single digit numbers, letters, and question marks, and check if there are exactly 3 question marks between every pair of two numbers that add up to 10. If so, then your program should return the string true, otherwise it should return the string false. If there aren't any two numbers that add up to 10 in the string, then your program should return false as well.

For example: if str is "arrb6???4xxbl5???eee5" then your program should return true because there are exactly 3 question marks between 6 and 4, and 3 question marks between 5 and 5 at the end of the string.
Examples
Input: "aa6?9"
Output: false
Input: "acc?7??sss?3rr1??????5"
Output: true

09) question_marks.java

import java.util.*; 
import java.io.*;
import java.util.regex.*;

10/10

class Main {  
  public static String QuestionsMarks(String str) { 
  
       str = str.replaceAll("[a-z]", "");
       Pattern pattern = Pattern.compile("([0-9])([?])([?])([?])([0-9])");
       Pattern falseP1 = Pattern.compile("([0-9])([?])([?])([0-9])");
       Pattern falseP2 = Pattern.compile("([0-9])([?])([0-9])");
       Matcher falseMatchP1 = falseP1.matcher(str);
       Matcher falseMatchP2 = falseP2.matcher(str);
       Matcher matchPattern = pattern.matcher(str);
       if (falseMatchP1.find() || falseMatchP2.find()){
           return "false";
       }
       if (matchPattern.find()){
           return "true";
       }
       return "false";
    
  } 

10) find_Intersection

Find Intersection
Have the function FindIntersection(strArr) read the array of strings stored in strArr which will contain 2 elements: the first element will represent a list of comma-separated numbers sorted in ascending order, the second element will represent a second list of comma-separated numbers (also sorted). Your goal is to return a comma-separated string containing the numbers that occur in elements of strArr in sorted order. If there is no intersection, return the string false.
Examples
Input: new String[] {"1, 3, 4, 7, 13", "1, 2, 4, 13, 15"}
Output: 1,4,13
Input: new String[] {"1, 3, 9, 10, 17, 18", "1, 4, 9, 10"}
Output: 1,9,10

11) find_intersection.java

import java.util.*; 
import java.io.*;

10/10

class Main {

  public static String FindIntersection(String[] strArr) {
     
    String str1 = strArr[0];
    String str2 = strArr[1];
    String result = "";

    String[] str1_arr = str1.split(", ");
    String[] str2_arr = str2.split(", ");
    
    for(String num_1: str1_arr)
    {
      for(String num_2: str2_arr)
      {
        if(num_1.equals(num_2)) // note = ! you can't num_1 == num_2 , it return false because they arent located in same memory area .
        {
          
          if(result.length()==0)
            result+=num_1;
          else 
            result+=","+num_1;
      
        }
      }
    }
    if(result.isEmpty())
      return "false";
    return result;
  }



  public static void main (String[] args) {  
    // keep this function call here     
    Scanner s = new Scanner(System.in);
    System.out.print(FindIntersection(s.nextLine())); 
  }

}