$ 123 328  51 64 
$  45 64  387 23 
$   6 98  215 314
$ *   +   *   +  

# &fras "input-6.txt" ◌

Calc ← (
  ↘₂⊛⊂"+*"/◇⊂
  ≡◇⨬(/+|/×)
  /+
)

P₁ ← (
  ⊜(⊜□⊸≠@ )⊸≠@\n
  ⊃⊣↘₋₁
  ⊙(⍉≡₀◇⋕)
  Calc
)

P₂ ← (
  ⊜∘⊸≠@\n
  ⟜⧻
  ⊓⍉(˜↯@ )
  ⊜(⊙(□≡⋕)⍜⍉(⊃(⊢⊣)↘₋₁))¬⤚≡⌟≍
  Calc
)

1_2 [⊃P₁P₂]
≡(&p &pf $"Part _: ")

use std::fs::File;
use std::io::{BufReader, Lines};

#[allow(dead_code)]
pub fn part1(input: Lines<BufReader<File>>) {
    let mut input = input
        .map_while(Result::ok)
        .map(|line| {
            line.split_ascii_whitespace()
                .map(|s| s.to_string())
                .collect::<Vec<String>>()
        })
        .collect::<Vec<Vec<String>>>();

    let ops = input.pop().unwrap();
    let values = input
        .iter()
        .map(|v| {
            v.iter()
                .map(|v| v.parse::<i64>().unwrap())
                .collect::<Vec<i64>>()
        })
        .collect::<Vec<Vec<i64>>>();

    let transposed: Vec<Vec<i64>> = (0..values[0].len())
        .map(|i| values.iter().map(|row| row[i]).collect())
        .collect();

    let mut sum = 0;
    for i in 0..ops.len() {
        let op: &str = &ops[i];
        match op {
            "+" => {
                sum += transposed[i].iter().sum::<i64>();
            }
            "*" => {
                sum += transposed[i].iter().product::<i64>();
            }
            _ => panic!("Invalid operation"),
        }
    }

    println!("sum = {}", sum)
}

#[allow(dead_code)]
pub fn part2(input: Lines<BufReader<File>>) {
    let mut input = input
        .map_while(Result::ok)
        .map(|line| line.chars().collect::<Vec<char>>())
        .collect::<Vec<Vec<char>>>();

    let ops = input
        .pop()
        .unwrap()
        .iter()
        .map(|c| c.to_string())
        .filter(|s| s != " ")
        .collect::<Vec<String>>();

    let transposed: Vec<i64> = (0..input[0].len())
        .map(|i| input.iter().map(|row| row[i]).collect())
        .map(|vec: String| vec.trim().to_string())
        .map(|s| {
            if s.len() == 0 {
                0
            } else {
                s.parse::<i64>().unwrap()
            }
        })
        .collect();

    let groups = transposed
        .into_iter()
        .fold(Vec::new(), |mut acc: Vec<Vec<i64>>, num| {
            if num == 0 {
                if let Some(last) = acc.last_mut() {
                    if !last.is_empty() {
                        acc.push(Vec::new());
                    }
                } else {
                    acc.push(Vec::new());
                }
            } else {
                if acc.is_empty() {
                    acc.push(Vec::new());
                }

                acc.last_mut().unwrap().push(num);
            }

            acc
        });

    let mut sum = 0;
    for i in 0..ops.len() {
        let op: &str = &ops[i];
        match op {
            "+" => {
                sum += groups[i].iter().sum::<i64>();
            }
            "*" => {
                sum += groups[i].iter().product::<i64>();
            }
            _ => panic!("Invalid operation"),
        }
    }

    println!("sum = {}", sum)
}

class Day06 : Puzzle {

    val numsPartOne = mutableListOf<MutableList<Long>>()
    val numsPartTwo = mutableListOf<List<Long>>()
    val ops = mutableListOf<(Long, Long) -> Long>()

    override fun readFile() {
        val input = readInputFromFile("src/main/resources/a2025/day06.txt")
        val lines = input.lines().filter { it.isNotBlank() }

        // parse part1 input
        for (line in lines.dropLast(1)) {
            for ((c, num) in line.trim().split(" +".toRegex()).withIndex()) {
                if (numsPartOne.getOrNull(c) == null) numsPartOne.add(mutableListOf())
                numsPartOne[c].add(num.toLong())
            }
        }

        // parse part2 input
        var numList = mutableListOf<Long>()
        for (c in 0..<lines.maxOf { it.length }) {
            var numStr = ""
            for (r in 0..<lines.size - 1) {
                numStr += lines[r].getOrElse(c) { ' ' }
            }
            if (numStr.isBlank()) {
                numsPartTwo.add(numList)
                numList = mutableListOf()
            } else {
                numList.add(numStr.trim().toLong())
            }
        }
        numsPartTwo.add(numList)

        // parse operators
        ops.addAll(
            lines.last().split(" +".toRegex())
                .map { it.trim()[0] }
                .map {
                    when (it) {
                        '*' -> { a: Long, b: Long -> a * b }
                        '+' -> { a: Long, b: Long -> a + b }
                        else -> throw IllegalArgumentException("Unknown operator: $it")
                    }
                }
        )
    }

    override fun solvePartOne(): String {
        return numsPartOne.mapIndexed { c, list -> list.reduce { a, b -> ops[c](a, b) } }.sum().toString()
    }

    override fun solvePartTwo(): String {
        return numsPartTwo.mapIndexed { c, list -> list.reduce { a, b -> ops[c](a, b) } }.sum().toString()
    }
}

func part2() {
	// file, _ := os.Open("sample.txt")
	file, _ := os.Open("input.txt")
	defer file.Close()
	scanner := bufio.NewScanner(file)

	chars := [][]rune{}
	for scanner.Scan() {
		chars = append(chars, []rune(scanner.Text()))
	}

	m := len(chars)
	n := len(chars[0])
	var op rune
	nums := []int{}
	total := 0

	for j := range n {
		current := []rune{}
		for i := range m {
			if chars[i][j] == '+' || chars[i][j] == '*' {
				op = chars[i][j]
			} else if chars[i][j] != ' ' {
				current = append(current, chars[i][j])
			}
		}
		if len(current) > 0 {
			x, _ := strconv.Atoi(string(current))
			nums = append(nums, x)
		}
		if len(current) == 0 || j == n-1 {
			result := 0
			if op == '*' {
				result = 1
			}
			for _, x := range nums {
				if op == '+' {
					result = result + x
				} else {
					result = result * x
				}
			}
			total += result
			nums = []int{}
		}
	}

	fmt.Println(total)
}

#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <ctype.h>
#include <assert.h>
#include <sys/mman.h>
#include <unistd.h>
#include <err.h>

#define GH	5

int
main()
{
	char *data, *g[GH], *p;
	uint64_t p1=0,p2=0, acc;
	int len, h=0, i, x,y, val;
	char op;

	if ((len = (int)lseek(0, 0, SEEK_END)) == -1)
		err(1, "<stdin>");
	if (!(data = mmap(NULL, len, PROT_READ, MAP_SHARED, 0, 0)))
		err(1, "<stdin>");
	for (i=0; i<len; i++)
		if (!i || data[i-1]=='\n') {
			assert(h < GH);
			g[h++] = data+i;
		}

	for (x=0; g[h-1]+x < data+len; x++) {
		if ((op = g[h-1][x]) != '+' && op != '*')
			continue;

		for (acc = op=='*', y=0; y<h-1; y++) {
			val = atoi(&g[y][x]);
			acc = op=='+' ? acc+val : acc*val;
		}

		p1 += acc;

		for (acc = op=='*', i=0; ; i++) {
			for (val=0, y=0; y<h-1; y++) {
				p = &g[y][x+i];
				if (p < g[y+1] && isdigit(*p))
					val = val*10 + *p-'0';
			}
			if (!val)
				break;
			acc = op=='+' ? acc+val : acc*val;
		}

		p2 += acc;
	}

	printf("06: %"PRIu64" %"PRIu64"\n", p1, p2);
}

package main

import (
	"aoc/utils"
	"fmt"
	"regexp"
	"slices"
	"strconv"
	"strings"
)

type operation int

func (o operation) compute(values []int) int {
	switch o {
	case add:
		sum := 0
		for _, val := range values {
			sum += val
		}
		return sum
	case mul:
		product := 1
		for _, val := range values {
			product *= val
		}
		return product
	}

	return 0
}

const (
	add operation = iota
	mul
)

var allOperationSymbols = []string{"+", "*"}

func operationFromSymbol(sym string) operation {
	switch sym {
	case "+":
		return add
	case "*":
		return mul
	default:
		panic(fmt.Sprintf("wtf is a %s?", sym))
	}
}

type problems struct {
	values     [][]int
	operations []operation
}

func (p *problems) feed(column string) {
	last := string(column[len(column)-1])
	done := false

	if slices.Contains(allOperationSymbols, last) {
		p.operations = append(p.operations, operationFromSymbol(last))
		column = column[:len(column)-1]
		done = true
	}

	val, _ := strconv.Atoi(strings.TrimSpace(column))
	idx := len(p.values) - 1
	p.values[idx] = append(p.values[idx], val)

	if done {
		p.values = append(p.values, []int{})
	}
}

func (p *problems) addLine(line string) (done bool) {
	parts := strings.Split(line, " ")
	parts = slices.DeleteFunc(parts, func(elem string) bool {
		return elem == ""
	})

	if slices.Contains(allOperationSymbols, parts[0]) {
		p.operations = make([]operation, len(parts))
		for idx, sym := range parts {
			p.operations[idx] = operationFromSymbol(sym)
		}
		done = true
	} else {
		if len(p.values) == 0 {
			lenparts := len(parts)
			p.values = make([][]int, lenparts)
			for idx := range lenparts {
				p.values[idx] = []int{}
			}
		}

		for idx, part := range parts {
			num, _ := strconv.Atoi(part)
			p.values[idx] = append(p.values[idx], num)
		}
		done = false
	}

	return done
}

func (p problems) solve() []int {
	solutions := make([]int, len(p.values))

	for idx, values := range p.values {
		op := p.operations[idx]
		solutions[idx] = op.compute(values)
	}

	return solutions
}

func stepOne(input chan string) (int, error) {
	modernProblems := problems{}
	for line := range input {
		done := modernProblems.addLine(line)
		if done {
			break
		}
	}

	modernSolutions := modernProblems.solve()
	sum := 0
	for _, solution := range modernSolutions {
		sum += solution
	}

	return sum, nil
}

func transposeInputChan(input chan string) []string {
	lines := [][]rune{}
	for line := range input {
		lines = append(lines, []rune(line))
	}

	linecount := len(lines)
	columncount := len(lines[0])
	transposed := make([][]rune, columncount)

	for idx := range transposed {
		transposed[idx] = make([]rune, linecount)
	}

	for row, line := range lines {
		for col, char := range line {
			transposed[col][row] = char
		}
	}

	columns := make([]string, len(transposed))
	for idx, col := range transposed {
		columns[idx] = string(col)
	}

	return columns
}

func stepTwo(input chan string) (int, error) {
	transposedInput := transposeInputChan(input)
	slices.Reverse(transposedInput)

	// problem-set with one empty problem.
	modernProblems := problems{
		values: [][]int{[]int{}},
	}

	for _, column := range transposedInput {
		if matched, _ := regexp.MatchString("^\\s*$", column); matched {
			continue
		}

		modernProblems.feed(column)
	}

	// Remove last useless empty problem.
	modernProblems.values = modernProblems.values[:len(modernProblems.values)-1]

	modernSolutions := modernProblems.solve()
	sum := 0
	for _, solution := range modernSolutions {
		sum += solution
	}

	return sum, nil
}

func main() {
	inputFile := utils.FilePath("day06.txt")
	utils.RunStep(utils.ONE, inputFile, stepOne)
	utils.RunStep(utils.TWO, inputFile, stepTwo)
}