dp[i][j]=Math.min(dp[i-1][j],dp[i][j-1])+grid[i][j];

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];
        //先初始化第0行和第0列
        for(int i=1;i<n;i++)
        {
            dp[0][i]=dp[0][i-1]+grid[0][i];
        }
        for(int j=1;j<m;j++)
        {
            dp[j][0]=dp[j-1][0]+grid[j][0];
        }
        //System.out.println(Arrays.deepToString(dp));
        for(int i=1;i<m;i++)
        {
            for(int j=1;j<n;j++)
            {
                dp[i][j]=Math.min(dp[i-1][j],dp[i][j-1])+grid[i][j];
            }
        }
        return dp[m-1][n-1];

    }