1) There are 3 subjects (A, B, C) and n students who write exams on these subjects. Allocate seats to these students such that no two students sit consecutively. That means if any student sits at position (i,j) then no other student should sit in position (i+1,j), (i,j+1), (i-1,j), (i,j-1) also two students with the same subject should not sit in the same row or column for example, A blank A is not a valid arrangement, whereas A blank B is a valid arrangement. 2) https://leetcode.com/problems/maximal-rectangle/description/