Advent of Code: Day 2

• Question here
• Input here

The Basic thing is to note that each

• win means 6 points
• draw means 3 points
• lose means 0 point

Part 1

Now in part 1,

• A and X means rock for 1 point
• B and Y means paper for 2 points
• C and Z means Scissor for 3 points

import java.io.File;
import java.util.Scanner;

public class Day2 {
    public static void main(String[] args) throws Exception {
        String path = "D:\\projects\\AdventOfCode\\src\\input.txt";
        File input = new File(path);
        Scanner sc = new Scanner(input);

        int points = 0;
        while (sc.hasNextLine()) {
            var line = sc.nextLine();
            char a = line.charAt(0);
            char b = line.charAt(2);

            if (b == 'X') { // rock
                if (a == 'A') { // rock
                    points += 4;
                } else if (a == 'B') { // paper
                    points += 1;
                } else { // scissor
                    points += 7;
                }
            } else if (b == 'Y') { // paper
                if (a == 'A') { // rock
                    points += 8;
                } else if (a == 'B') { // paper
                    points += 5;
                } else { // scissor
                    points += 2;
                }
            } else { // scissor
                if (a == 'A') { // rock
                    points += 3;
                } else if (a == 'B') { // paper
                    points += 9;
                } else { // scissor
                    points += 6;
                }
            }
        }

        System.out.println(points);
        sc.close();
    }
}

Part 2

For this part,

• X means lose = 0 point
• Y means draw = 3 points
• Z means win = 6 points

therefore we have to find the counter move for ourself according to the play by opponent i.e for eg.

if the condition is to lose and opponent plays a rock, we have to play a scissor.

import java.io.File;
import java.util.Scanner;

public class Day2 {
    public static void main(String[] args) throws Exception {
        String path = "D:\\projects\\AdventOfCode\\src\\input.txt";
        File input = new File(path);
        Scanner sc = new Scanner(input);

        int points = 0;
        while (sc.hasNextLine()) {
            var line = sc.nextLine();
            char a = line.charAt(0);
            char b = line.charAt(2);

            if (b == 'X') { // lose
                if (a == 'A') { // need scissor
                    points += 3;
                } else if (a == 'B') { // need rock
                    points += 1;
                } else { // need paper
                    points += 2;
                }
            } else if (b == 'Y') { // draw
                if (a == 'A') { // need rock
                    points += 4;
                } else if (a == 'B') { // need paper
                    points += 5;
                } else { // need scissor
                    points += 6;
                }
            } else { // win
                if (a == 'A') { // need paper
                    points += 8;
                } else if (a == 'B') { // need scissor
                    points += 9;
                } else { // need rock
                    points += 7;
                }
            }
        }

        System.out.println(points);
        sc.close();
    }
}