Amazon Interview Question: How many smaller cubes are co... | Glassdoor

How many smaller cubes are completely invisible in a n*n*n

rubic's cube?

3

n^3- 6n^2

The number of cubes are n^3(volume).
The number of cubes exposing one or more sides( 6 *( n^2) - all cubes on the sides.)
Number of invisible cubes are n^3- 6n^2 .

Vivekananda on Jun 7, 2012
3

Isn't the answer none since the question says "completely invisible"? every unit is visible by at least one side so any sub cube (made of these units) has a portion exposed.

luis on Jun 13, 2012
5

N*N*N-(N*N*2+N*(N-2)*2+(N-2)*(N-2)*2)

ram on Jun 13, 2012
18

(N-2)^3

Sofya on Jun 25, 2012
3

(n-2)^3 you can verify by assuming n=4. Try to visualize invisible cubes and compare it with answers.

Raj on Apr 28, 2014
5

(n-2)^3 you can verify by assuming n=4. Try to visualize invisible cubes and compare it with answers.

Raj on Apr 28, 2014

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