• Coins on a star

 

Can somebody help me with this problem from book algorithmic puzzles ?

The object of this puzzle is to place the largest possible number of coins at points of the eight-pointed star depicted in Figure 2.9. The coins should be placed one after another, with the following restrictions: (i) a coin needs to be placed first on an unoccupied point and then moved along a line to another unoccupied point, and (ii) once a coin has been positioned in this manner, it cannot be moved again. For example, we can start by placing the first coin on point 6 and then moving it to point 1 (denoted 6 → 1), where the coin will have to remain. We can continue, say, with the following sequence of moves: 7 → 2, 8 → 3, 7 → 4, 8 → 5, which places five coins.

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