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#![allow(dead_code)]
#![allow(unused_variables)]
#![allow(unused_mut)]
use std::collections::HashSet;
use std::env;
use std::fs::File;
use std::io::Read;
fn dfs(x0: i64, y0: i64, map: &Vec<Vec<i64>>, mut hs: HashSet<(i64, i64)>) -> HashSet<(i64, i64)> {
//println!("{} {}", x0, y0);
let h = map.len() as i64;
let w = map[0].len() as i64;
let n = map[y0 as usize][x0 as usize];
if n == 9 {
hs.insert((y0, x0));
return hs;
}
for (dx, dy) in [(0, 1), (0, -1), (1, 0), (-1, 0)] {
let x = x0 + dx as i64;
let y = y0 + dy as i64;
if (0 <= x) && (x < w) && (0 <= y) && (y < h) {
if map[y as usize][x as usize] == n + 1 {
hs = dfs(x, y, map, hs);
}
}
}
return hs;
}
fn dfs2(x0: i64, y0: i64, map: &Vec<Vec<i64>>) -> i64 {
let h = map.len() as i64;
let w = map[0].len() as i64;
let n = map[y0 as usize][x0 as usize];
if n == 9 {
return 1;
}
let mut score = 0;
for (dx, dy) in [(0, 1), (0, -1), (1, 0), (-1, 0)] {
let x = x0 + dx as i64;
let y = y0 + dy as i64;
if (0 <= x) && (x < w) && (0 <= y) && (y < h) {
if map[y as usize][x as usize] == n + 1 {
score += dfs2(x, y, map);
}
}
}
return score;
}
fn main() {
let args: Vec<String> = env::args().collect();
let filename = if args.len() == 1 {
"in/".to_owned() + args[0].split('/').last().unwrap() + ".pzl"
} else {
args[1].clone()
};
let mut f = File::open(filename).expect("cannot open file");
let mut content = String::new();
f.read_to_string(&mut content).expect("cannot read file");
let lines = content.trim_end().split("\n");
let mut trailheads: Vec<(i64, i64)> = Vec::new();
let mut map: Vec<Vec<i64>> = Vec::new();
for (y, line) in lines.enumerate() {
let mut l: Vec<i64> = Vec::new();
for (x, c) in line.chars().enumerate() {
let n = c.to_digit(10).unwrap() as i64;
l.push(n);
if n == 0 {
trailheads.push((x as i64, y as i64));
}
}
map.push(l);
}
let mut res1 = 0;
let mut res2 = 0;
for (x0, y0) in trailheads {
let hs = dfs(x0, y0, &map, HashSet::new());
res1 += hs.len();
res2 += dfs2(x0, y0, &map);
}
println!("res1: {}", res1);
println!("res2: {}", res2);
assert_eq!(res1, 607);
assert_eq!(res2, 1384);
}
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