Thursday, August 19, 2010

Puzzle: Slicing a pizza in 3 parts

This is a nice puzzle when you are with your friends and you eat a pizza. There are two guys and a pizza. How can you cut the pizza so that everyone is happy about the slice received? This is pretty easy for 2 guys, but how about 3 guys and , more generally, n guys?


  1. here is my approach when I eat pizza:

    Each friend gets a slice with angle 360/n.

    Hence, for three friends each one gets a slice
    with angle 120 degrees.

    The real question is how do we estimate the
    angle when we are in front of a pizza and no
    protractor is available?

  2. this is not a solution, you just postponed the problem.

  3. ok, here the algorithm.
    1) from an arbitrary participant, clockwise: each participant makes his own cut (from the center, like a radius);
    2) with same order: each participant chooses his the bigger slice from the 2 slices in front of him.

    Alternative: anticlockwise :)
    I'll run some tests this weekend with friends ;)

    BTW, how is life in London? I'm missing Lipari times ;)