ChocolatesByNumbers – Codility – Solution

Java solution to Codility ChocolatesByNumbers problem (Lesson 12 – Euclidean algorithm) which scored 100%. The problem is to count the number of chocolates you will eat when there are N chocolates in a circle.

The strategy is to divide N by the greatest common divisor of N and M.

Reference

Solution to Chocolates-By-Numbers (Code Says)

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package com.codility.lesson12.euclidean;

public class ChocolatesByNumbers {
  public int solve(int N, int M) {
    return N / gcdByDivision(N, M);
  }
 
  int gcdByDivision(int A, int B) {
    if(A % B == 0) return B;
    else           return gcdByDivision(B, A % B);
  }
 
}

TestNG test cases for this problem which all passed:

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package test.com.codility.lesson12.euclidean;

import org.testng.Assert;
import org.testng.annotations.BeforeTest;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;

import com.codility.lesson12.euclidean.ChocolatesByNumbers;

public class ChocolatesByNumbersTests {
  private ChocolatesByNumbers solution;
 
  @BeforeTest
  public void setUp() {
    solution = new ChocolatesByNumbers();
  }

  @DataProvider(name = "data1")
  public Object [][] createData1() {
    return new Object [][] {
      new Object [] { 10, 4, 5 },
      new Object [] { 10, 3, 10 },
      new Object [] { 5, 6, 5 },
      new Object [] { 5, 7, 5 },
      new Object [] { 1, 1, 1 },
      new Object [] { 2, 1, 2 },
      new Object [] { 100, 1, 100 },
    };
  }
 
  @Test(dataProvider = "data1")
  public void verifySolution(int pN, int pM, int pExpected) {    
    Assert.assertEquals(solution.solve(pN, pM), pExpected);  
  }
}