solve(ANS,12).
choice2([3,14,6,9], [ ], ANS, 0, 12)
H=3,T=[14,6,9],L=[],
X=0,SUM=12
Y=3
choice2([14,6,9], [3], ANS, 3, 12)
choice2([6,9], [0,3], ANS, 3, 12)
choice2([9], [0,0,3], ANS, 3, 12)
choice2([ ], [0,0,0,3], ANS, 3, 12)
SUM=3,SUM=12 不一致
(失敗)