newton插值法求给定插值点的插值函数，也可求某点的函数值，本算法用了我自己定义的Poly类，这是一个处理多项式的类，希望能够和大家分享-newton interpolation for a given interpolation point interpolation function, but also a point-resort function, the algorithm I used Poly-defined categories, this is a deal with the