AoC Day 1 Part 2

DayOne.java

package in.stonecolddev;

import java.util.List;
import java.util.Map;

public class DayOne implements DayRunner {

  public static String partOne(List<String> data) {
    Integer sum = 0;

    for (String line : data) {
      Integer firstNumber = null;
      Integer lastNumber = null;
      Integer numbersSeen = 0;

      for (char c : line.toCharArray()) {
        if (Character.isDigit(c)) {
          numbersSeen++;
          Integer numericValue = Character.getNumericValue(c);
          if (firstNumber == null) {
            firstNumber = numericValue;
          } else {
            lastNumber = numericValue;
          }
        }
      }

      if (numbersSeen < 2) {
        lastNumber = firstNumber;
      }
      sum += Integer.parseInt("%d%d".formatted(firstNumber, lastNumber));
    }

    return sum.toString();
  }

  public static String partTwo(List<String> data) {
    Integer sum = 0;

    for (String line : data) {
      Integer firstNumber = null;
      Integer lastNumber = null;
      Integer numbersSeen = 0;
      Map<String, Integer> numbers = Map.of(
        "one", 1,
        "two", 2,
        "three", 3,
        "four", 4,
        "five", 5,
        "six", 6,
        "seven", 7,
        "eight", 8,
        "nine", 9);

      for (String number : numbers.keySet().stream().sorted().toList()) {
        System.out.printf("Checking %s for number %d%n", line, numbers.get(number));
        if (line.toLowerCase().contains(number)) {
          numbersSeen++;
          Integer actualNumber = numbers.get(number);
          if (firstNumber == null) {
            firstNumber = actualNumber;
            System.out.printf("%d is the first number%n", firstNumber);
          } else {
            lastNumber = actualNumber;
            System.out.printf("%d is the last number%n", lastNumber);
          }
        }
      }

      for (char c : line.toCharArray()) {
        if (Character.isDigit(c)) {
          numbersSeen++;
          if (firstNumber == null) {
            firstNumber = Character.getNumericValue(c);
          } else {
            lastNumber = Character.getNumericValue(c);
          }
        }
      }

      if (numbersSeen < 2) {
        lastNumber = firstNumber;
      }
      sum += Integer.parseInt("%d%d".formatted(firstNumber, lastNumber));
    }

    return sum.toString();
  }
}