Calculate the Total Amount of Points Using Java


The challenge

Our football team finished the championship. The result of each match look like “x:y”. Results of all matches are recorded in the collection.

For example: ["3:1", "2:2", "0:1", ...]

Write a function that takes such collection and counts the points of our team in the championship. Rules for counting points for each match:

  • if x>y – 3 points
  • if x<y – 0 point
  • if x=y – 1 point

Notes:

  • there are 10 matches in the championship
  • 0 <= x <= 4
  • 0 <= y <= 4

Test cases

import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;

public class SolutionTest {
    @Test
    public void basicTests() {
        assertEquals(30, TotalPoints.points(new String[]
                         {"1:0","2:0","3:0","4:0","2:1","3:1","4:1","3:2","4:2","4:3"}));
                     
        assertEquals(10, TotalPoints.points(new String[]
                         {"1:1","2:2","3:3","4:4","2:2","3:3","4:4","3:3","4:4","4:4"}));
                     
        assertEquals(0, TotalPoints.points(new String[]
                         {"0:1","0:2","0:3","0:4","1:2","1:3","1:4","2:3","2:4","3:4"}));
        
        assertEquals(15, TotalPoints.points(new String[]
                         {"1:0","2:0","3:0","4:0","2:1","1:3","1:4","2:3","2:4","3:4"}));
                     
        assertEquals(12, TotalPoints.points(new String[]
                         {"1:0","2:0","3:0","4:4","2:2","3:3","1:4","2:3","2:4","3:4"}));
    }
}

The solution in Java

Option 1:

public class TotalPoints {
  
  public static int points(String[] games) {
    int points = 0;
    
    for (String item: games) {
      int x = (int) item.charAt(0);
      int y = (int) item.charAt(2);
      if (x>y) points += 3;
      else if (x==y) points ++;
    }
    
    return points;
  }
}

Option 2 (using a stream):

import java.util.Arrays;
public class TotalPoints {
  
    public static int points(String[] games) {
       return Arrays.stream(games)
                     .mapToInt(score -> score.charAt(0) - score.charAt(2))
                     .map(match -> match > 0 ? 3 : match == 0 ? 1 : 0)
                     .sum();
    }
}