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Const-ify winning indices

This commit is contained in:
kageru 2021-12-04 16:00:05 +01:00
parent ea1339f018
commit df68a385d8
Signed by: kageru
GPG Key ID: 8282A2BEA4ADA3D2
1 changed files with 18 additions and 10 deletions
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28
2021/src/bin/day04.rs
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@ -5,9 +5,24 @@ use itertools::Itertools;
const DAY: usize = 4;
const BOARD_SIZE: usize = 5;
const NUMBERS_PER_BOARD: usize = BOARD_SIZE * BOARD_SIZE;
type Board = Vec<Vec<u8>>;
const WINNING_INDICES: [[usize; BOARD_SIZE]; BOARD_SIZE * 2] = {
let mut out = [[0; BOARD_SIZE]; BOARD_SIZE * 2];
let mut i = 0;
while i < BOARD_SIZE {
// tfw there are no for loops in const fn
let mut j = 0;
while j < BOARD_SIZE {
out[i][j] = i * 5 + j;
out[BOARD_SIZE + i][j] = i + j * 5;
j += 1;
}
i += 1;
}
out
};
#[derive(Debug, Clone)]
struct BingoGame {
input_numbers: Vec<u8>,
@ -47,15 +62,8 @@ fn parse_input(raw: &str) -> BingoGame {
.split("\n\n")
.map(|b| b.split_ascii_whitespace().map(|n| n.parse().unwrap()).collect())
.map(|v: Vec<u8>| {
debug_assert_eq!(v.len(), NUMBERS_PER_BOARD);
// This seems way too complicated. What am I missing?
(0..NUMBERS_PER_BOARD)
.chain((0..BOARD_SIZE).flat_map(|i| (i..NUMBERS_PER_BOARD).step_by(BOARD_SIZE)))
.map(|i| v[i])
.chunks(BOARD_SIZE)
.into_iter()
.map(|c| c.collect())
.collect()
debug_assert_eq!(v.len(), BOARD_SIZE * BOARD_SIZE);
WINNING_INDICES.map(|row_or_col| row_or_col.map(|i| v[i]).to_vec()).to_vec()
})
.collect();
BingoGame { input_numbers, boards }