IMO Shortlist 2012 problem C3
In a
square table some cells are white and the remaining ones are red. Let
be the number of triples
of cells, the first two in the same row and the last two in the same column, with
white and
red. Find the maximum value
can attain.
%V0
In a $999 \times 999$ square table some cells are white and the remaining ones are red. Let $T$ be the number of triples $(C_1,C_2,C_3)$ of cells, the first two in the same row and the last two in the same column, with $C_1,C_3$ white and $C_2$ red. Find the maximum value $T$ can attain.
Source: Međunarodna matematička olimpijada, shortlist 2012