Advent of Code 2021 - Day 1

///usr/bin/env jbang "$0" "$@" ; exit $?


import static java.lang.System.*;

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Collections;
import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.IntConsumer;
import java.util.function.ToLongBiFunction;
import java.util.stream.IntStream;

public class Day1 {


    static class Mapper implements IntStream.IntMapMultiConsumer {

        private int last = -1;

        @Override
        public void accept(int t, IntConsumer u) {

            if (last >= 0 && t > last)
                u.accept(1);

            last = t;

        }

    }


    static record Window(int a, int b, int c) {
        int sum() {
            return a + b + c;
        }

        boolean isValid() {
            return a >= 0 && b >= 0 && c >= 0;
        }
    }

    static class Windower implements BiConsumer<Integer, Consumer<Window>> {
        private int a = -1;
        private int b = -1;
        private int c = -1;

        @Override
        public void accept(Integer t, Consumer<Window> u) {
            a = b;
            b = c;
            c = t;
            u.accept(new Window(a, b, c));
        }

    }

    static IntStream lines() {
        try  {
            return Files.readAllLines(Paths.get("input.txt")).stream().mapToInt(Integer::parseInt);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        throw new RuntimeException();
    }

    static void part1() {
        final Mapper mapper = new Mapper();
        final Integer sum = lines().mapMulti(mapper).sum();
        out.println("Part 1: " + sum);
    }

    static void part2() {
        final Mapper mapper = new Mapper();
        final Windower windower = new Windower();
        final Integer sum = lines()
            .boxed()
            .mapMulti(windower)
            .filter(Window::isValid)
            .mapToInt(Window::sum)
            .mapMulti(mapper)
            .sum();

        out.println("Part 2: " + sum);

    }
    public static void main(String... args) {
        part1();
        part2();
    }
}