You are given an integer n . You have an n x n binary grid grid with all values initially 1 's except for some indices given in the array mines . The i ^th element of the array mines is defined as mines[i] = [x _i , y _i ] where grid[x _i ][y _i ] == 0 .
Return the order of the largest axis-aligned plus sign of 1 's contained in grid . If there is none, return 0 .
An axis-aligned plus sign of 1 's of order k has some center grid[r][c] == 1 along with four arms of length k - 1 going up, down, left, and right, and made of 1 's. Note that there could be 0 's or 1 's beyond the arms of the plus sign, only the relevant area of the plus sign is checked for 1 's.
1 <= n <= 5001 <= mines.length <= 50000 <= x _i , y _i < nAll the pairs (x _i , y _i ) are unique .