/**
 * [64] Minimum Path Sum
 */
pub struct Solution {}

// submission codes start here

impl Solution {
    pub fn min_path_sum(grid: Vec<Vec<i32>>) -> i32 {
        let (m, n) = (grid.len(), grid[0].len());
        let mut dp = vec![vec![0; n]; m];

        for i in 0..m {
            for j in 0..n {
                if i == 0 {
                    if j == 0 {
                        dp[i][j] = grid[i][j];
                    } else {
                        dp[i][j] = dp[i][j - 1] + grid[i][j];
                    }
                } else {
                    if j == 0 {
                        dp[i][j] = dp[i - 1][j] + grid[i][j];
                    } else {
                        dp[i][j] = dp[i - 1][j].min(dp[i][j - 1]) + grid[i][j];
                    }
                }
            }
        }

        dp[m - 1][n - 1]
    }
}

// submission codes end

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_64() {
        assert_eq!(
            7,
            Solution::min_path_sum(vec![vec![1, 3, 1], vec![1, 5, 1], vec![4, 2, 1]])
        );
    }
}