MinPathSum(leetcode)

题目：
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.

题解如下：

public int minPathSum(int[][] grid) {           if(grid==null||grid.length==0||grid[0].length==0) {            return 0;        }        int [][]dp=new int [grid.length][grid[0].length];        dp[0][0]=grid[0][0];        for(int i=1;i<grid.length;i++) {            dp[i][0]=grid[i][0]+dp[i-1][0];        }        for(int i=1;i<grid[0].length;i++) {            dp[0][i]=grid[0][i]+dp[0][i-1];        }        for(int i=1;i<grid.length;i++) {            for(int j=1;j<grid[0].length;j++) {                if(dp[i-1][j]>dp[i][j-1]) {                    dp[i][j]=dp[i][j-1]+grid[i][j];                }else {                    dp[i][j]=dp[i-1][j]+grid[i][j];                }            }        }        return dp[grid.length-1][grid[0].length-1];    }