A diamond mine is an R-row by C-column grid of 0s and 1s.
A diamond is the boundary of a square made of 1s after the square is rotated by 45 degrees. Diamonds of sizes 1, 2, and 3 look like this:
size 1: size 2: size 3: 1 1 1 1 1 1 1 1 1 1 1 1 1
Write a program that finds the size of the largest diamond that can be formed in the grid.
Input
The first line contains R and C. Both R and C are positive integers no greater than 750. Each of the next R lines describes one row of the diamond mine using 0s and 1s.
Output
Print the size of the largest diamond in the mine. If there is no diamond, print 0.
cho.sh