pastemyst | aoc day 8

aoc day 8

main.rs

Rustcopy raw

use std::io::{self, Read};

fn main() {
    let mut stdin = io::stdin();
    let mut buf: String = String::new();
    stdin.read_to_string(&mut buf).unwrap();
    let trees: Vec<Vec<i8>> = buf.split("\n").map(|f| f.chars().map(|c| c.to_digit(10).unwrap() as i8).collect::<Vec<i8>>()).collect();
    // let mut visible: Vec<Vec<bool>> = vec![vec![false; trees.len()]; trees.len()];
    
    // // from top
    // for i in 0..trees.len() {
    //     let mut most: i8 = -1;
    //     for j in 0..trees[i].len() {
    //         if most < trees[i][j] {
    //             visible[i][j] = true;
    //             most = trees[i][j];
    //         }
    //     }
    // }
    // // from left
    // for j in 0..trees[0].len() {
    //     let mut most: i8 = -1;
    //     for i in 0..trees.len() {
    //         if most < trees[i][j] {
    //             visible[i][j] = true;
    //             most = trees[i][j];
    //         }
    //     }
    // }
    // // from bottom
    // for i in 0..trees.len() {
    //     let mut most: i8 = -1;
    //     for j in (0..trees[i].len()).rev() {
    //         if most < trees[i][j] {
    //             visible[i][j] = true;
    //             most = trees[i][j];
    //         }
    //     }
    // }
    // // from right
    // for j in 0..trees[0].len() {
    //     let mut most: i8 = -1;
    //     for i in (0..trees.len()).rev() {
    //         if most < trees[i][j] {
    //             visible[i][j] = true;
    //             most = trees[i][j];
    //         }
    //     }
    // }

// let visible_rows = visible.iter().map(|v| v.iter().fold(0, |a, b| if *b {a+1} else {a}));
    // let visible_total = visible_rows.reduce(|a, b| a+b);
    // println!("{}", visible_total.unwrap());

let mut best_score = 0;
    for i in 0..trees.len() {
        for j in 0..trees[i].len() {
            let mut right: usize = 0;
            let lowest = trees[i][j];
            loop {
                if j+right == trees[i].len() - 1 { break; }
                right += 1;
                if lowest <= trees[i][j+right] { break; }
            }
            let mut left: usize = 0;
            loop {
                if j-left == 0 { break; }
                left += 1;
                if lowest <= trees[i][j-left] { break; }
            }
            let mut down: usize = 0;
            loop {
                if i+down == trees.len() - 1 { break; }
                down += 1;
                if lowest <= trees[i+down][j] { break; }
            }
            let mut up: usize = 0;
            loop {
                if i-up == 0 { break; }
                up += 1;
                if lowest <= trees[i-up][j] { break; }
            }
            let result = right * left * down * up;
            if result > best_score { best_score = result; }
        }
    }
    println!("{}", best_score);
}

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