当前你的浏览器版本过低，网站已在兼容模式下运行，兼容模式仅提供最小功能支持，网站样式可能显示不正常。
请尽快升级浏览器以体验网站在线编辑、在线运行等功能。
Given a m-by-n (0,1)-matrix, of all its submatrices of all 1’s which is the largest? By largest we mean that the submatrix has the most elements.
The input contains multiple test cases. Each test case begins with m and n (1 ≤ m, n ≤ 2000) on line. Then come the elements of a (0,1)-matrix in row-major order on m lines each with n numbers. The input ends once EOF is met.
For each test case, output one line containing the number of elements of the largest submatrix of all 1’s. If the given matrix is of all 0’s, output 0.
2 2 0 0 0 0 4 4 0 0 0 0 0 1 1 0 0 1 1 0 0 0 0 0
0 4
| Case time limit(单组数据时间限制) | 2000MS |
| 时间上限 | 内存上限 |
| 5000 | 131072 |