Given a binary matrix, find out the largest size square sub-matrix with all 1's and return its area.
Input
matrix: a binary matrix
Output
the area of the largest square in the input matrix
Examples
Example 1
Input
matrix =
[[1, 0, 1, 0, 0],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 0],
[1, 0, 0, 1, 0]]
Output: 4
Explanation
The largest square is of size 2x2 and area 4.