AoC 2023 day 13 part 1

fn main() {
    let input = std::fs::read_to_string("../inputs/input.txt").unwrap();

    let mut above_sum = 0;
    let mut left_sum = 0;

    for block in input.split("\n\n") {
        let block: Vec<Vec<char>> = block.lines().map(|line| line.chars().collect()).collect();
        above_sum += count_above_reflect_point(&block);
        let transposed = transpose(&block);
        left_sum += count_above_reflect_point(&transposed);
    }

    println!("part 1: {}", left_sum + 100 * above_sum);
}

fn transpose(block: &[Vec<char>]) -> Vec<Vec<char>> {
    let mut transposed: Vec<Vec<char>> = Vec::new();
    let block_height = block.len();
    let block_width = block[1].len();

    for x in 0..block_width {
        let mut v = Vec::with_capacity(block_height);
        for y in 0..block_height {
            v.push(block[y][x]);
        }
        transposed.push(v);
    }
    transposed
}

fn count_above_reflect_point(block: &[Vec<char>]) -> u32 {
    for i in 1..block.len() {
        if block[i] == block[i - 1] {
            let before = &block[..i];
            let after = &block[i..];
            if before.iter().rev().zip(after.iter()).all(|(a, b)| a == b) {
                return i as u32;
            }
        }
    }
    0
}