this post was submitted on 31 Dec 2024
4 points (100.0% liked)

Advent Of Code

997 readers
1 users here now

An unofficial home for the advent of code community on programming.dev!

Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.

AoC 2024

Solution Threads

M T W T F S S
1
2 3 4 5 6 7 8
9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25

Rules/Guidelines

Relevant Communities

Relevant Links

Credits

Icon base by Lorc under CC BY 3.0 with modifications to add a gradient

console.log('Hello World')

founded 2 years ago
MODERATORS
[email protected]
Sigmatics
[email protected]
4
[SOLVED] need help with day 7 part 1 of adventofcode (self.advent_of_code)
submitted 2 months ago* (last edited 2 months ago) by kionite231 to c/[email protected]
10 comments fedilink hide all child comments
 

Hello,

I am trying to solve the day 7 using Rust and this is what I came up with so far:

use std::fs;

fn calculate(answer: &i32, numbers: &mut Vec<i32>) -> bool {
    if numbers.len() >= 2 {
	let tmp1 = numbers[0];
	let tmp2 = numbers[1];
	numbers.remove(0);
	numbers.remove(0);

	numbers.insert(0, tmp1 * tmp2);

	if calculate(answer, numbers) == true {
	    return true;
	} else {
	    numbers.remove(0);
	    numbers.insert(0, tmp1 + tmp2);
	    if calculate(answer, numbers) == true {
		return true;
	    } else {
		return false;
	    }
	}
    } else {
	if *answer == numbers[0] {
	    println!("> {} true", numbers[0]);
	    return true;
	} else {
	    println!("> {} false", numbers[0]);
	    return false;
	}
    }
}

fn main() {
    let contents = fs::read_to_string("sample.txt")
        .expect("Should have been able to read the file");

    for line in contents.lines() {
	let tmp = line.split(":").collect::<Vec<&str>>();
	let answer = tmp[0].to_string().parse::<i32>().unwrap();
	println!("{:?}", answer);
	let numbers_str = tmp[1].split(" ");
	let mut numbers: Vec<i32> = Vec::new();
	for num in numbers_str {
	    if num.len() == 0 {
		continue;
	    }
	    numbers.push(num.parse::<i32>().unwrap());
	}
	println!("{:?}", numbers);
	if calculate(&answer, &mut numbers) == true {
	    println!("it's true");
	}
    }
}

I don't know why the recursion is not working. any help would be appreciated.

you are viewing a single comment's thread
view the rest of the comments
[โ€“] ImplyingImplications 2 points 2 months ago (1 children)

In case this helps too, here's the Python version of your code (with print statements removed):

def calculate(answer: int, numbers: list[int]) -> bool:
    if len(numbers) >= 2:
        tmp1 = numbers[0]
        tmp2 = numbers[1]
        numbers = numbers[2:]

        numbers.insert(0, tmp1*tmp2)

        if calculate(answer, numbers):
            return True
        else:
            numbers = numbers[1:]
            numbers.insert(0, tmp1+tmp2)
            return calculate(answer, numbers)
    else:
        return answer == numbers[0]
[โ€“] kionite231 1 points 2 months ago

Thanks I will try to run the python version and see if it works. I think the problem is that I am passing list of numbers by reference and in python it's passed by value, this is the reason the python version works while mine doesn't.