Minimum Path Sum java

//注意下，二维数组长度的使用方法public class Solution {    public int minPathSum(int[][] grid) {    if(grid == null || grid.length == 0)        return -1;    for(int i = 1;i<grid.length;i++)        grid[i][0] = grid[i-1][0] + grid[i][0];     for(int j = 1;j<grid[0].length;j++)        grid[0][j] = grid[0][j-1] + grid[0][j];    for(int i = 1;i<grid.length;i++)        for(int j = 1;j<grid[0].length;j++)        {               int min = 0;            if(grid[i-1][j]<grid[i][j-1])                min = grid[i-1][j];            else                min = grid[i][j-1];            grid[i][j] = grid[i][j] + min;        }    return grid[grid.length-1][grid[0].length-1];    }}

本题目主要收获是，数组的length在二维数组中的使用。