// duynotes.blogspot.com
class Solution {
    public int minPathSum(int[][] grid) {
        int m = grid.length;
        int n = grid[0].length;
        int [][] dp = new int[m][n];
        
        dp[0][0] = grid[0][0];
        
        for (int i=1; i<m; i++){
            dp[i][0] = dp[i-1][0]+grid[i][0];
        }
        
        for (int j=1; j<n; j++){
            dp[0][j] = dp[0][j-1]+grid[0][j];
        }
        
        for (int i=1; i<m; i++){
            for (int j=1; j<n; j++){
                dp[i][j] = Math.min(dp[i-1][j]+grid[i][j],dp[i][j-1]+grid[i][j]);
            }
        }
        return dp[m-1][n-1];
    }
}