试题 也许是因为有 10 个手指的原因，所以我们把 0～9 十个数字组合起来表达任意的数值，但这并不是唯一可能的记数法。在某个外星球居住着一种智慧生物，他们的手跟我们的手构造不同，他们的记数法也很奇特。他们用三个记号’0’,’1’,’-’的组合来表达数值，这三个记号分别对应数值 0,1,-1。-Questions may be because of the reasons for the 10 fingers, so we have 0 ~ 9 to 10 the number of combinations of arbitrary numerical expression, but this is not the only possible notation. Living in a planet outside a biological wisdom, they hand in hand with our structure is different from the notation that they are very strange. Their mark with three' 0 ' ,' 1' ,'-'　to express a combination of value, corresponding to the three marked values 0,1,-1.