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Clean up solution to day 1.

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Bert Peters
2016-12-02 11:19:00 +01:00
parent 9f0b9b4ef8
commit 6937fec0fd
1 changed files with 22 additions and 30 deletions
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48
2016/day-01/solution.rs
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@@ -6,12 +6,21 @@ use std::io::prelude::*;
use std::path::Path; use std::path::Path;
use std::str; use std::str;
fn dist(pos: (i32, i32)) -> i32 { fn dist(pos: (i32, i32)) -> i32
{
let (x, y) = pos; let (x, y) = pos;
return x.abs() + y.abs() return x.abs() + y.abs()
} }
fn walk(pos: (i32, i32), dir: i32) -> (i32, i32)
{
let backwards = if dir & 2 == 2 { -1 } else { 1 };
let (x, y) = pos;
(x + backwards * (1 - (dir & 1)), y + backwards * (dir & 1))
}
fn main() { fn main() {
let args: Vec<String> = env::args().collect(); let args: Vec<String> = env::args().collect();
let path = Path::new(&args[1]); let path = Path::new(&args[1]);
@@ -33,13 +42,12 @@ fn main() {
Ok(_) => {}, Ok(_) => {},
}; };
let mut posx = 0; let mut pos = (0, 0);
let mut posy = 0;
let mut dir = 0; let mut dir = 0;
let mut found = false; let mut found = false;
let mut positions = HashSet::new(); let mut positions = HashSet::new();
positions.insert((posx, posy)); positions.insert(pos);
for instruction in content.split(", ") { for instruction in content.split(", ") {
let turn = &instruction[..1]; let turn = &instruction[..1];
@@ -51,36 +59,20 @@ fn main() {
if turn == "R" { if turn == "R" {
dir += 1; dir += 1;
} else { } else {
dir -= 1; dir += 3;
} }
dir = (dir + 4) % 4; dir %= 4;
let backwards = if dir & 2 == 2 { -1 } else { 1 }; for _ in 0..steps {
if dir & 1 == 1 { pos = walk(pos, dir);
// Move in y direction if !found && positions.contains(&pos) {
for y in 1..(steps + 1) { println!("Visited twice at dist {}", dist(pos)) ;
if positions.contains(&(posx, posy + y * backwards)) && !found {
found = true;
println!("Arrived at the same position, dist {}", dist((posx, posy + y * backwards)));
} else {
positions.insert((posx, posy + y * backwards));
}
}
posy += steps * backwards;
} else {
// Move in x direction
for x in 1..(steps + 1) {
if positions.contains(&(posx + x * backwards, posy)) && !found {
println!("Arrived at the same position, dist {}", dist((posx + x * backwards, posy)));
found = true; found = true;
} else { } else {
positions.insert((posx + x * backwards, posy)); positions.insert(pos);
} }
} }
posx += steps * backwards;
}
} }
println!("Total distance is {}", dist((posx, posy))) println!("Total distance is {}", dist(pos));
} }