Packing 1x1x4 bricks into a 6x6x6 box
Question
Is it possible to fit rectangular bricks, each , inside a box?
Short answer
No. Split the box into blocks of size and colour them black and white like a 3D chessboard: black blocks ( cells) and white ( cells). Any brick runs through two blocks of each colour, covering white cells, so at most bricks fit, even though .
Adapted from Zhou, A Practical Guide to Quantitative Finance Interviews, sec. 2.3 Thinking Out of the Box, 'Box packing', p.9; question and answer rewritten by SelfMadeQuant.com.
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