Table of content

What is this :grey_question:

The rules of the game are explained in my original.

85th Challenge

Challenge

Like every year, I am going to participate in the Advent of Code. Lets get started with advent of code

Solution :white_check_mark: 


use itertools::Itertools;

fn main() {

    let symbols = vec![0, 1, 3]; 
    let input = include_str!("input.txt");

    let x = input.lines().map(|line| {
        let line = line.replace(":", "");
        let mut line = line.split(" ").collect::<Vec<&str>>();
        let result = line.remove(0).parse::<i64>().unwrap();
        let numbers = line.iter().map(|x| x.parse::<i64>().unwrap()).collect::<Vec<i64>>();
        (result, numbers)
    }).fold(0, |acc, x| {
        let permutations = std::iter::repeat(symbols.clone()).take(x.1.len())
        .multi_cartesian_product();
        
        for perm in permutations {
            let values: Vec<_> = perm;
            let sum = values.iter().enumerate().fold(0, |acc, k| {
                
                match k.1{
                    0 => {
                        acc + x.1[k.0]
                    },
                    1 => {
                        acc * x.1[k.0]
                    },
                    3 => {
                        let digits = count_digits(x.1[k.0]);
                        acc*10i64.pow(digits) + x.1[k.0]
                    },
                    _ => panic!("Invalid symbol")
                }
            });

            if sum == x.0 {
                return acc + sum;
            }
        }
        acc
    });

    println!("x: {:?}", x);
}

fn count_digits(n: i64) -> u32 {
    if n == 0 {
        1
    } else {
        (n.abs() as f64).log10().floor() as u32 + 1
    }
}