60 lines
1.7 KiB
Rust
60 lines
1.7 KiB
Rust
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use std::env;
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use std::fs;
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fn main() {
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let input = fs::read_to_string(&env::args().nth(1).unwrap()).unwrap();
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let forest: Vec<Vec<i8>> = input.lines()
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.map(|line| line.chars()
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.map(|c| c.to_digit(10).unwrap() as i8).collect())
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.collect();
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let nrows = forest.len();
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let ncols = forest[0].len();
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let min_from_left: Vec<Vec<i8>> = forest.iter()
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.map(|row| row.iter()
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.scan(-1, |h, &tree| {
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let old = *h; *h = i8::max(*h as i8, tree); Some(old)
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})
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.collect())
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.collect();
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let min_from_right: Vec<Vec<i8>> = forest.iter()
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.map(|row: &Vec<i8>| row.iter()
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.rev()
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.scan(-1, |h, &tree| {
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let old = *h; *h = i8::max(*h as i8, tree); Some(old)
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})
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.collect::<Vec<i8>>().iter()
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.rev().map(|x| *x)
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.collect())
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.collect();
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let mut min_from_top: Vec<Vec<i8>> = vec![vec![-1; ncols]; nrows];
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for c in 0..ncols {
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for r in 1..nrows {
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min_from_top[r][c] = i8::max(min_from_top[r-1][c], forest[r-1][c]);
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}
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}
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let mut min_from_bot: Vec<Vec<i8>> = vec![vec![-1; ncols]; nrows];
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for c in 0..ncols {
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for r in (0..nrows-1).rev() {
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min_from_bot[r][c] = i8::max(min_from_bot[r+1][c], forest[r+1][c]);
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}
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}
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let mut sum = 0;
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for r in 0..nrows {
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for c in 0..ncols {
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if forest[r][c] > min_from_left[r][c]
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|| forest[r][c] > min_from_right[r][c]
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|| forest[r][c] > min_from_top[r][c]
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|| forest[r][c] > min_from_bot[r][c] {
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sum += 1;
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}
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}
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}
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println!("{:?}", sum);
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}
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