#P2213. [USACO14MAR] The Lazy Cow S
[USACO14MAR] The Lazy Cow S
题目描述
It's a hot summer day, and Bessie the cow is feeling quite lazy. She wants
to locate herself at a position in her field so that she can reach as much
delicious grass as possible within only a short distance.
The field Bessie inhabits is described by an N by N grid of square cells
(1 <= N <= 400). The cell in row r and column c (1 <= r,c <= N) contains
G(r,c) units of grass (0 <= G(r,c) <= 1000). From her initial square in
the grid, Bessie is only willing to take up to K steps (0 <= K <= 2*N).
Each step she takes moves her to a cell that is directly north, south,
east, or west of her current location.
For example, suppose the grid is as follows, where (B) describes Bessie's
50 5 25* 6 17
14 3* 2* 7* 21
99* 10* 1*(B) 2* 80*
8 7* 5* 23* 11
10 0 78* 1 9
initial position (here, in row 3, column 3):
If K=2, then Bessie can only reach the locations marked with *s.
Please help Bessie determine the maximum amount of grass she can reach, if
she chooses the best possible initial location in the grid.
奶牛贝茜非常懒惰,她希望在她的地盘内找到一点最佳位置居住,以便在有限的步数内可以吃到尽量多的青草。
她的地盘是一个 的矩阵,第 行 列包含 单位的青草 。从她的居住点,她最多愿意走 步 ,每一步她可以走到上与她相邻的某个格子。
输入格式
* Line 1: The integers N and K.
* Lines 2..1+N: Line r+1 contains N integers describing row r of the
grid.
输出格式
* Line 1: The maximum amount of grass Bessie can reach, if she chooses
the best possible initial location (the location from which
she can reach the most grass).
5 2
50 5 25 6 17
14 3 2 7 21
99 10 1 2 80
8 7 5 23 11
10 0 78 1 9
342
提示
OUTPUT DETAILS:
In the example above, Bessie can reach 342 total units of grass if she
locates herself in the middle of the grid.
Source: USACO 2014 March Contest, Silver