oj mrJudge
Toggle navigation
  • Login
    • Forget Password
      Login
User Image

Hello, Stranger

Guest
  • Analysis Mode
  • Problems
    • All Problems
    • Latest Problems
  • Join Us Now
  • Registration
  • Contact Us
  • Infomation
  • About
    • Terms of Use
    • Technical Specifications
    • Credits

fliprect Batch , stdin/stdout

Registered Users Only

Please login to utilize this feature.

Do note that this website only supports submissions in C++.

fliprect.html

Title

Problem Statement

We have a board with an H × W grid. Each square in the grid is painted in black or white. The square at the i-th row from the top and j-th column from the left is black if the j-th character in Si is #, and white if that character is ..

Snuke can perform the following operation on the grid any number of times:

  • Select a row or column in the grid, and invert the color of all the squares in that row or column (that is, black squares become white and vice versa).

Then, Snuke draws a rectangle along grid lines. Here, all the squares contained in the rectangle must be painted in black.

Find the maximum possible area of Snuke's rectangle when the operation is performed optimally.

Constraints

  • 2 ≤ H ≤ 2000
  • 2 ≤ W ≤ 2000
  • |Si| = W
  • Si consists of # and ..

Input

Input is given from Standard Input in the following format:

H W
S1
S2
:
SH

Output

Print the maximum possible area of Snuke's rectangle.

Sample Input 1

3 3
..#
##.
.#.

Sample Output 1

6

If the first row from the top and the third column from the left are inverted, a 2 × 3 rectangle can be drawn, as shown below:

Sample Input 2

4 4
....
....
....
....

Sample Output 2

16

Sample Input 3

10 8
##...#.#
##...#.#
..###.#.
#.##.#.#
.#..#.#.
..##.#.#
##.#.#..
...#.#..
###.#.##
###..###

Sample Output 3

27

Tags

atCoder

Subtasks and Limits

Subtask Score #TC Time Memory Scoring
1100371s256MBMinimum
2031s256MBMinimum

Judge Compile Command

g++-8 ans.cpp -o fliprect -Wall -Wshadow -static -O2 -lm -m64 -s -w -std=gnu++17 -fmax-errors=512

Accepted Submissions

subIDUserTimeMax Time

Past Submissions

subIDUserTimeScore
mrJudge 09.05.20
Copyright © 2020 mrJudge. All rights reserved.