说明：  为使问题一般化，本题的三次样条求解使用了对于任意分化的三弯矩插值法。若记各节点间距 ，根据理论分析，三次样条插值函数
(In order to generalize the problem, cubic spline used to solve this problem for any of the three differentiation moment interpolation. If the distance between each node in mind, according to the theoretical analysis, cubic spline interpolation function)