26 lines
915 B
Rust
26 lines
915 B
Rust
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struct Solution {}
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impl Solution {
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fn indices(grid: &[Vec<i32>]) -> impl Iterator<Item = (isize, isize)> + '_ {
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(0..grid.len()).flat_map(move |y| (0..grid[y].len()).map(move |x| (x as isize, y as isize)))
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}
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fn in_range(grid: &[Vec<i32>], y: isize, x: isize) -> bool {
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y >= 0 && y < grid.len() as isize && x >= 0 && x < grid[y as usize].len() as isize
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}
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fn count_empty(grid: &[Vec<i32>], y: isize, x: isize) -> i32 {
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[-1, 1]
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.into_iter()
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.flat_map(|d| [(x + d, y), (x, y + d)])
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.filter(|&(x, y)| !Self::in_range(grid, y, x) || grid[y as usize][x as usize] == 0)
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.count() as i32
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}
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pub fn island_perimeter(grid: Vec<Vec<i32>>) -> i32 {
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Self::indices(&grid)
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.filter(|&(x, y)| grid[y as usize][x as usize] != 0)
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.map(|(x, y)| Self::count_empty(&grid, y, x))
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.sum()
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}
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}
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