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| 1 | +/* |
| 2 | + * [0980] unique-paths-iii |
| 3 | + */ |
| 4 | + |
| 5 | +pub struct Solution {} |
| 6 | + |
| 7 | +// solution impl starts here |
| 8 | + |
| 9 | +impl Solution { |
| 10 | + pub fn unique_paths_iii(grid: Vec<Vec<i32>>) -> i32 { |
| 11 | + let mut grid = grid; |
| 12 | + let (mut x, mut r, mut c) = (1, 0, 0); |
| 13 | + for ir in 0..grid.len() { |
| 14 | + let row = &grid[ir]; |
| 15 | + for ic in 0..row.len() { |
| 16 | + if row[ic] == 0 { |
| 17 | + x += 1; |
| 18 | + } else if row[ic] == 1 { |
| 19 | + r = ir as i32; |
| 20 | + c = ic as i32; |
| 21 | + } |
| 22 | + } |
| 23 | + } |
| 24 | + |
| 25 | + Solution::dfs(&mut grid, r, c, x) |
| 26 | + } |
| 27 | + |
| 28 | + fn dfs(grid: &mut Vec<Vec<i32>>, r: i32, c: i32, x: i32) -> i32 { |
| 29 | + if r < 0 |
| 30 | + || c < 0 |
| 31 | + || r >= grid.len() as i32 |
| 32 | + || c >= grid[0].len() as i32 |
| 33 | + || grid[r as usize][c as usize] == -1 |
| 34 | + { |
| 35 | + return 0; |
| 36 | + } |
| 37 | + |
| 38 | + let (ur, uc) = (r as usize, c as usize); |
| 39 | + if grid[ur][uc] == 2 { |
| 40 | + return if x == 0 { 1 } else { 0 }; |
| 41 | + } |
| 42 | + |
| 43 | + grid[ur][uc] = -1; |
| 44 | + let res = Solution::dfs(grid, r + 1, c, x - 1) |
| 45 | + + Solution::dfs(grid, r - 1, c, x - 1) |
| 46 | + + Solution::dfs(grid, r, c + 1, x - 1) |
| 47 | + + Solution::dfs(grid, r, c - 1, x - 1); |
| 48 | + grid[ur][uc] = 0; |
| 49 | + res |
| 50 | + } |
| 51 | +} |
| 52 | + |
| 53 | +// solution impl ends here |
| 54 | + |
| 55 | +// solution tests starts here |
| 56 | + |
| 57 | +#[cfg(test)] |
| 58 | +mod tests { |
| 59 | + use super::*; |
| 60 | + |
| 61 | + #[test] |
| 62 | + fn test_case0() { |
| 63 | + assert_eq!( |
| 64 | + Solution::unique_paths_iii(vec![vec![1, 0, 0, 0], vec![0, 0, 0, 0], vec![0, 0, 2, -1]]), |
| 65 | + 2 |
| 66 | + ); |
| 67 | + } |
| 68 | + |
| 69 | + #[test] |
| 70 | + fn test_case1() { |
| 71 | + assert_eq!( |
| 72 | + Solution::unique_paths_iii(vec![vec![1, 0, 0, 0], vec![0, 0, 0, 0], vec![0, 0, 0, 2]]), |
| 73 | + 4 |
| 74 | + ); |
| 75 | + } |
| 76 | + |
| 77 | + #[test] |
| 78 | + fn test_case2() { |
| 79 | + assert_eq!(Solution::unique_paths_iii(vec![vec![0, 1], vec![2, 0]]), 0); |
| 80 | + } |
| 81 | +} |
| 82 | + |
| 83 | +// solution tests ends here |
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