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Java Exercises: Form a staircase shape of n coins where every k-th row must have exactly k coins

Java Basic: Exercise-109 with Solution

Write a Java program to form a staircase shape of n coins where every k-th row must have exactly k coins.

Example 1:
n = 3
The coins can form the following rows:
$
$ $
We will return 2 rows.
Example 2:
n = 4
The coins can form the following rows:
$
$ $
$
We will return 2 rows as the 3rd row is incomplete.
Example 3:
n = 5
The coins can form the following rows:
$
$ $
$ $
We will return 2 rows as the 3rd row is incomplete.

Sample Solution:

Java Code:

import java.util.Scanner;
public class Example109 {
     public static void main(String[] arg) {
	  Scanner in = new Scanner(System.in);	
       System.out.print("Input a positive integer: ");
        int n = in.nextInt(); 
		if (n>0)
		{
           System.out.println("Number of rows: "+((int)((Math.sqrt(8 * (long)n + 1) - 1) / 2)));	
		}       	
	}	
}

Sample Output:

Input a positive integer: 5                                            
Number of rows: 2 

Flowchart:

Flowchart: Java exercises: Form a staircase shape of n coins where every k-th row must have exactly k coins

Java Code Editor:

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Java: Tips of the Day

getEnumMap

Converts to enum to Map where key is the name and value is Enum itself.

public static <E extends Enum<E>> Map<String, E> getEnumMap(final Class<E> enumClass) {
    return Arrays.stream(enumClass.getEnumConstants())
            .collect(Collectors.toMap(Enum::name, Function.identity()));
}

Ref: https://bit.ly/3xXcFZt