Minimum Path Sum

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.

Note: You can only move either down or right at any point in time.

这个题目跟triangle 其实是一样的，可以放一起做。

这个代码基本跟答案一样了，不需要再看答案了。

public class Solution {
    public int minPathSum(int[][] grid) {
        if (grid == null || grid.length == 0 || grid[0].length == 0) {
            return 0;
        }
        
        int row = grid.length;
        int col = grid[0].length;
        int sum[][] = new int[row][col];
        sum[0][0] = grid[0][0];
        for (int i = 1; i < col; i++) {
            sum[0][i] = sum[0][i-1] + grid[0][i];
        }
        for (int i = 1; i < row; i++) {
            sum[i][0] = sum[i-1][0] + grid[i][0];
        }
        for (int i = 1; i < row; i++) {
            for (int j = 1; j < col; j++){
                sum[i][j] = Math.min(sum[i-1][j], sum[i][j-1]) + grid[i][j];
            }
        }
        
        return sum[row-1][col-1];
    }
}