leet-code/valid-sudoku/sol_functional.rs

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Rust
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2022-06-04 11:25:07 +00:00
// A more functional (and much worse imo) solution
impl Solution {
#[inline]
pub fn contains_duplicate(row: &Vec<char>) -> bool {
let mut map = 0;
row
.iter()
.filter_map(|chr| {
if *chr != '.' {
return Some(1 << (*chr as usize - 49));
}
None
})
.any(|chr| {
if map & chr != 0 {
return true;
}
map |= chr;
false
})
}
pub fn is_valid_sudoku(board: Vec<Vec<char>>) -> bool {
!(
board.iter() // Rows
.any(|row| Solution::contains_duplicate(row)) ||
(0..9).into_iter() // Columns
.map(|idx| board.iter()
.map(|row| row[idx])
.collect::<Vec<char>>()
)
.any(|row| Solution::contains_duplicate(&row)) ||
(0..9).into_iter() // 3 by 3 squares
.map(|idx| {
let (row_idx, col_idx) = (idx as usize / 3, idx as usize % 3);
board.iter()
.enumerate()
.filter_map(|(r, row)| {
if r / 3 == row_idx {
return Some(row[col_idx*3..(col_idx*3 + 3)].to_vec());
}
None
})
.flatten()
.collect::<Vec<char>>()
})
.any(|row| Solution::contains_duplicate(&row))
)
}
}