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struct Solution;

impl Solution {
    fn unique_paths_with_obstacles(obstacle_grid: Vec<Vec<i32>>) -> i32 {
        let n = obstacle_grid.len();
        let m = obstacle_grid[0].len();
        let mut dp = vec![vec![0; m]; n];
        dp[0][0] = 1;
        for i in 0..n {
            for j in 0..m {
                if obstacle_grid[i][j] == 0 {
                    if i > 0 {
                        dp[i][j] += dp[i - 1][j];
                    }
                    if j > 0 {
                        dp[i][j] += dp[i][j - 1];
                    }
                } else {
                    dp[i][j] = 0;
                }
            }
        }
        dp[n - 1][m - 1]
    }
}

#[test]
fn test() {
    let obstacle_grid = vec_vec_i32![[0, 0, 0], [0, 1, 0], [0, 0, 0]];
    let res = 2;
    assert_eq!(Solution::unique_paths_with_obstacles(obstacle_grid), res);
    let obstacle_grid = vec_vec_i32![[1]];
    let res = 0;
    assert_eq!(Solution::unique_paths_with_obstacles(obstacle_grid), res);
}