L9_A
最大公因數
Greatest Common Divisor
河內塔
Tower of Hanoi
L9_B
三座城堡
Three Castles
sample code:
https://gist.github.com/htchen/e86a7d4293d6b33e2dce
四個皇后
Four Queens
sample code:
https://gist.github.com/htchen/f0082a35ff9d04231cfd