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#![allow(dead_code)]
#![allow(unused_variables)]
#![allow(unused_mut)]
use num::complex::Complex as c;
use num::Complex;
use std::cmp::min;
use std::collections::HashMap;
use std::collections::HashSet;
use std::fs::File;
use std::io::Read;
type Matrix<T> = Vec<Vec<T>>;
fn bfs1(m: &Matrix<u32>) -> u32 {
let mut s: HashMap<(Complex<i32>, Complex<i32>, u32), u32> = HashMap::new();
let mut hs: HashSet<(Complex<i32>, Complex<i32>, u32, u32)> = HashSet::new();
let mut hs_next: HashSet<(Complex<i32>, Complex<i32>, u32, u32)> = HashSet::new();
hs.insert((c::new(0, 0), c::new(1, 0), 0, 0));
let mut res: Vec<u32> = Vec::new();
while hs.len() > 0 {
for (pos, dir, conti, mut hl) in hs {
if conti > 2 {
continue;
}
if !(0 <= pos.re
&& pos.re < m[0].len() as i32
&& 0 <= pos.im
&& pos.im < m.len() as i32)
{
continue;
}
hl += m[pos.im as usize][pos.re as usize];
if pos == c::new(m[0].len() as i32 - 1, m.len() as i32 - 1) {
res.push(hl);
continue;
}
if let Some(hl_) = s.get(&(pos, dir, conti)) {
if hl_ <= &hl {
continue;
}
}
s.insert((pos, dir, conti), hl);
let new_dir = dir;
let new_pos = pos + new_dir;
hs_next.insert((new_pos, new_dir, conti + 1, hl));
let new_dir = dir * c::i();
let new_pos = pos + new_dir;
hs_next.insert((new_pos, new_dir, 0, hl));
let new_dir = dir * (-c::i());
let new_pos = pos + new_dir;
hs_next.insert((new_pos, new_dir, 0, hl));
}
hs = hs_next;
hs_next = HashSet::new();
}
return res.into_iter().fold(999999999, min) - m[0][0];
}
fn bfs2(m: &Matrix<u32>) -> u32 {
let mut s: HashMap<(Complex<i32>, Complex<i32>, u32), u32> = HashMap::new();
let mut hs: HashSet<(Complex<i32>, Complex<i32>, u32, u32)> = HashSet::new();
let mut hs_next: HashSet<(Complex<i32>, Complex<i32>, u32, u32)> = HashSet::new();
hs.insert((c::new(0, 0), c::new(1, 0), 0, 0));
let mut res: Vec<u32> = Vec::new();
while hs.len() > 0 {
for (pos, dir, conti, mut hl) in hs {
if conti > 9 {
continue;
}
if !(0 <= pos.re
&& pos.re < m[0].len() as i32
&& 0 <= pos.im
&& pos.im < m.len() as i32)
{
continue;
}
hl += m[pos.im as usize][pos.re as usize];
if conti > 2 && pos == c::new(m[0].len() as i32 - 1, m.len() as i32 - 1) {
res.push(hl);
continue;
}
if let Some(hl_) = s.get(&(pos, dir, conti)) {
if hl_ <= &hl {
continue;
}
}
s.insert((pos, dir, conti), hl);
let new_dir = dir;
let new_pos = pos + new_dir;
hs_next.insert((new_pos, new_dir, conti + 1, hl));
if conti > 2 {
let new_dir = dir * c::i();
let new_pos = pos + new_dir;
hs_next.insert((new_pos, new_dir, 0, hl));
let new_dir = dir * (-c::i());
let new_pos = pos + new_dir;
hs_next.insert((new_pos, new_dir, 0, hl));
}
}
hs = hs_next;
hs_next = HashSet::new();
}
return res.into_iter().fold(999999999, min) - m[0][0];
}
fn main() {
// let filename = "in/day17.ref";
let filename = "in/day17.pzl";
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 m: Matrix<u32> = Vec::new();
for line in lines {
let mut mr: Vec<u32> = Vec::new();
for c in line.chars() {
mr.push(c.to_digit(10).unwrap());
}
m.push(mr);
}
let res1 = bfs1(&m);
let res2 = bfs2(&m);
println!("res1: {}", res1);
println!("res2: {}", res2);
assert_eq!(res1, 635);
assert_eq!(res2, 734);
}
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