OpenJudge

3:To the Max

总时间限制:
5000ms
内存限制:
65536kB
描述
Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1*1 or greater located within the whole array. The sum of a rectangle is the sum of all the elements in that rectangle. In this problem the sub-rectangle with the largest sum is referred to as the maximal sub-rectangle.
As an example, the maximal sub-rectangle of the array:

0 -2 -7 0
9 2 -6 2
-4 1 -4 1
-1 8 0 -2
is in the lower left corner:

9 2
-4 1
-1 8
and has a sum of 15.
输入
The input consists of an N * N array of integers. The input begins with a single positive integer N on a line by itself, indicating the size of the square two-dimensional array. This is followed by N^2 integers separated by whitespace (spaces and newlines). These are the N^2 integers of the array, presented in row-major order. That is, all numbers in the first row, left to right, then all numbers in the second row, left to right, etc. N may be as large as 500. The numbers in the array will be in the range [-127,127].
输出
Output the sum of the maximal sub-rectangle.
样例输入
4
0 -2 -7 0 9 2 -6 2
-4 1 -4  1 -1

8  0 -2
样例输出
15
来源
Greater New York 2001
全局题号
52
提交次数
628
尝试人数
168
通过人数
167