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SKP’s Algorithms and Data Structures #9: Java Problem: Monkeys in the Garden

[Question/Problem Statement is the Property of Techgig] 

Monkeys in the Garden [www.techgig.com]

In a garden, trees are arranged in a circular fashion with an equal distance between two adjacent trees. The height of trees may vary. Two monkeys live in that garden and they were very close to each other. One day they quarreled due to some misunderstanding. None of them were ready to leave the garden. But each one of them wants that if the other wants to meet him, it should take maximum possible time to reach him, given that they both live in the same garden.

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SKP’s Algorithms and Data Structures #8: Java Problem: Simple Inheritance (OOPs)

[Question/Problem Statement is the Property of Techgig]
 
Java Inheritance / Simple OOPs [www.techgig.com]
Create Two Classes:

BaseClass
The Rectangle class should have two data fields-width and height of int types. The class should have display() method, to print the width and height of the rectangle separated by space.

DerivedClass
The RectangleArea class is Derived from Rectangle class, i.e., it is the Sub-Class of Rectangle class. The class should have read_input() method, to Read the Values of width and height of the Rectangle. The RectangleArea class should also Overload the display() Method to Print the Area (width*height) of the Rectangle.

Input Format
The First and Only Line of Input contains two space-separated Integers denoting the width and height of the Rectangle.

Constraints
1 <= width,height <= 10^3

Output Format
The Output Should Consist of Exactly Two Lines.
In the First Line, Print the Width and Height of the Rectangle Separated by Space.
In the Second Line, Print the Area of the Rectangle.


[Explanation of the Solution]
This is the Simplest of all OOPs Questions! Demonstration of Inheritance and Overriding (Very Loosely, Liskov Substitution of SOLID).


[Source Code, Sumith Puri (c) 2021 — Free to Use and Distribute]
Java
 




x
67


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 /*
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  * Techgig Core Java Basics Problem - Get Simple OOPs Right!
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  * Author: Sumith Puri [I Bleed Java!]; GitHub: @sumithpuri;
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  */
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  import java.io.*;
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  import java.util.*;
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  class Rectangle {
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    private int width;
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    private int height;
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    public void display() {
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      System.out.println(width + " " + height);
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    }
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    public int getWidth() {
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      return width;
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    }
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    public void setWidth(int width) {
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      this.width=width;
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    }
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    public int getHeight() {
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      return height;
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    }
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    public void setHeight(int height) {
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      this.height=height;
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    }
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  }
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  class RectangleArea extends Rectangle {
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    public void read_input() {
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     Scanner scanner = new Scanner (System.in);
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     setWidth(scanner.nextInt());
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     setHeight(scanner.nextInt());
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    }
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    public void display() {
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      super.display();
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      System.out.println(getWidth()*getHeight());
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    }
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  }
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  public class CandidateCode {
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   public static void main(String args[] ) throws Exception {
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     RectangleArea rectangleArea = new RectangleArea();
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     rectangleArea.read_input();
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     rectangleArea.display();
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   }
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 }



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SKP’s Algorithms and Data Structures #7: Functional Programming and Java Lambdas

[Question/Problem Statement is the Property of Techgig]

Java Advanced — Lambda Expressions [www.techgig.com] 
Write the Following Methods that Return a Lambda Expression Performing a Specified Action: Perform Operation isOdd(): The Lambda Expression must return if a Number is Odd or  If it is Even. Perform Operation isPrime(): The lambda expression must return if a number is prime or if it is composite. PerformOperation isPalindrome(): The Lambda Expression must return if a number is a Palindrome or if it is not.

Input Format
Input is as Show in the Format Below
Input
3
1 3
2 7
3 7777

Constraints
NA

Output Format
Output is as Show in the Format Below
Output
ODD
PRIME
PALINDROME


[Explanation of the Solution]
This is a Good Question to Refresh Java 8 Lambdas. In my Solution, I Implemented the Functional Interfaces within my main() Method and assigned it to Local Reference Variables.


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SKP’s Algorithms and Data Structures #6: Java Problem: Active Traders

[Question/Problem Statement is the Property of HackerRank]

Algorithms/Data Structures — [Problem Solving] 
An Institutional Broker wants to Review their Book of Customers to see which are Most Active. Given a List of Trades By "Customer Name, Determine which Customers Account for At Least 5% of the Total Number of Trades. Order the List Alphabetically Ascending By Name."


Example
n = 23
"customers = {"Bigcorp", "Bigcorp", "Acme", "Bigcorp", "Zork", "Zork", "Abe", "Bigcorp", "Acme", "Bigcorp", "Bigcorp", "Zork", "Bigcorp", "Zork", "Zork", "Bigcorp", "Acme", "Bigcorp", "Acme", "Bigcorp", "Acme", "Littlecorp", "Nadircorp"}."

"Bigcorp had 10 Trades out of 23, which is 43.48% of the Total Trades."
"Both Acme and Zork had 5 trades, which is 21.74% of the Total Trades."
"The Littlecorp, Nadircorp, and Abe had 1 Trade Each, which is 4.35%..."

"So the Answer is ["Acme","Bigcorp","Zork"] (In Alphabetical Order) Because only These Three Companies Placed at least 5% of the Trades.


Function Description
Complete the Function mostActive in the Editor Below.

mostActive has the following parameter:
String customers[n]: An Array Customer Names
(Actual Question Says String Array, But Signature is List of Strings)

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SKP’s Algorithms and Data Structures #5: Java Problem: Changes in Usernames

[Question/Problem Statement is the Adapted from HackerRank]

Algorithms/Data Structures — [Problem Solving] 
There is a Specific Need for Changes in a List of Usernames. In a given List of Usernames — For Each Username — If the Username can be Modified and Moved Ahead in a Dictionary. The Allowed Modification is that Alphabets can change Positions in the Given Username.

Example
usernames[] = {"Aba", "Cat"}
 
"Aba" can be Changed to only "Baa" — Hence, It can Never Find a Place Ahead in the Dictionary. Hence, Output will be "NO". "Cat" can be Changed to "Act", "Atc", "Tca", "Tac", "Cta" and Definitely "Act" will Find a Place Before "Cat" in the Dictionary. Hence, Output will be "YES".

[Function Description]
Complete the function possibleChanges in the Editor Below.
 
possibleChanges has the Following Parameters:
String usernames[n]: An Array of User Names
 
Returns String[n]: An Array with "YES" or "NO" Based on Feasibility
(Actual Question Says String Array, But Signature is List of Strings)


Constraints
• [No Special Constraints Exist, But Cannot Recall Exactly]


Input Format 
"The First Line Contains an Integer, n, the Number of Elements in Usernames.",
"Each Line of the n Subsequent Lines (where 0 < i < n) contains a String usernames[i]."        

[Sample Case 0 — Sample Input For Custom Testing]         
5
Aba
Cat
Boby
Buba
Bapg
Sungi
Lapg
Acba
       
Sample Output (Each Should Be on a Separate Line) 
NO YES NO YES YES YES YES YES
   
 
[Explanation of the Solution]
This is again a Good Question from Hacker Rank to Test Your Logic / Problem Solving Abilities. The Core Point to Handle is that For Each Combination of 2 Alphabets that Exists in the Username String > We Need to Check if the Latter Occurring Character (ASCII) is Less than the Former Occurring Character (ASCII). For Example in the String "Bapg" — For a Selection of "Ba" from "Bapg" — We have "a" Occurring Before "B" in the English Alphabet. We can Have Two Loops (One Nested) to Decide for a Combination of Each Two Alphabets. The Time Complexity of this Solution is O(n^2).
 


[Source Code, Sumith Puri (c) 2021 — Free to Use and Distribute]

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SKP’s Java/Java EE Gotchas: Clash of the Titans, C++ vs. Java!

As a Software Engineer, the mind is trained to seek optimizations in every aspect of development and ooze out every bit of available CPU Resource to deliver a performing application. This begins not only in designing the algorithm or coming out with efficient and robust architecture but right onto the choice of programming language. Most of us, as we spend years in our jobs — tend to be proficient in at least one of these.  
 
Recently, I spent some time checking on the Performance (not a very detailed study) of the various programming languages. One, by researching on the Internet; Two, by developing small programs and benchmarking. The legacy languages — be it ASM or C still rule in terms of performance. But these are definitely ruled out for enterprise applications due to the complexity in development, maintainability, need for object orientation, and interoperability. They still will win for mission-critical or real-time systems, which need performance over these parameters. There were languages I briefly read about, including other performance comparisons on the internet. These include Python, PHP, Perl, and Ruby. Considering all aspects and needs of current enterprise development, it is C++ and Java which outscore the other in terms of speed. According to other comparisons [Google for 'Performance of Programming Languages'] spread over the net, they clearly outshine others in all speed benchmarks. So much for my blog title :-) So when these titans are pit against each other in real-time, considering all aspects of memory and execution time — Java is floored. Though I have spent the last ~17 years (In 2021) of my life coding and perfecting my Java and J2EE skill — I suddenly feel... Ahem, Slow! One of the problem statements to verify this is given below (along with the associated code) and the associated execution parameters. 
 


[Disclaimer: Problem Statement given below is the property of www.codechef.com] 

In Byteland they have a very strange monetary system. Each Bytelandian gold coin has an integer number written on it. A coin n can be exchanged in a bank into three coins: n/2, n/3, and n/4. But these numbers are all rounded down (the banks have to make a profit). You can also sell Bytelandian coins for American dollars. The exchange rate is 1:1. But you can not buy Bytelandian coins. You have one gold coin. What is the maximum amount of American dollars you can get for it? Input The input will contain several test cases (not more than 10). Each test case is a single line with a number n, 0 <= n <= 1 000 000 000. It is the number written on your coin. 
 
JAVA SOLUTION (Will Be Uploaded Later)
C++ SOLUTION (Will Be Uploaded Later)
 
RESULTS

TIME