Henry Ernest Dudeney/Puzzles and Curious Problems/249 - Odds and Evens/Solution

by : $249$

 * Odds and Evens

Solution
The fewest possible moves are as follows, given by ordered pairs of the letters identifying the circles from and to which the counters are moved.


 * $\tuple {E, A}, \tuple {E, B}, \tuple {E, C}, \tuple {E, D}, \tuple {B, D}, \tuple {E, B},$
 * $\tuple {C, B}, \tuple {A, B}, \tuple {E, C}, \tuple {E, A}, \tuple {B, A}, \tuple {C, E},$
 * $\tuple {B, C}, \tuple {A, C}, \tuple {B, A}, \tuple {C, B}, \tuple {C, A}, \tuple {B, A},$
 * $\tuple {E, C}, \tuple {E, B}, \tuple {C, B}, \tuple {D, E}, \tuple {D, B}, \tuple {E, B}$

That is, $24$ moves.