diff options
| -rw-r--r-- | 2017/src/bin/day03.rs | 32 |
1 files changed, 5 insertions, 27 deletions
diff --git a/2017/src/bin/day03.rs b/2017/src/bin/day03.rs index 4f38ac3..8a556a1 100644 --- a/2017/src/bin/day03.rs +++ b/2017/src/bin/day03.rs @@ -1,42 +1,20 @@ use std::io::{self, Read}; -// 17 16 15 14 13 -// 18 5 4 3 12 -// 19 6 1 2 11 -// 20 7 8 9 10 -// 21 22 23---> ... -// -// 1 R -// 1 U -// 2 L -// 2 D -// 3 R -// 3 U -// 4 L -// 4 D -// 5 R - fn solve1(input: i32) -> i32 { - let ds = [(1, 0), (0, 1), (-1, 0), (0, -1)]; - + let spiral = [(1, 0), (0, 1), (-1, 0), (0, -1)]; + let (mut x, mut y) = (0i32, 0i32); let mut n = 1; - let mut x = 0i32; - let mut y = 0i32; - let mut r = 1; - let mut i = 0; - for &(dx, dy) in ds.iter().cycle() { - for _ in 0..r { + for (i, &(dx, dy)) in spiral.iter().cycle().enumerate() { + let length = 1 + i / 2; + for _ in 0..length { if n == input { return x.abs() + y.abs(); } - n += 1; x += dx; y += dy; } - r += i % 2; - i += 1; } unreachable!() } |