algorithm-in-python/dataStructure/polynomial.py

''' mbinary
#########################################################################
# File : polynomial.py
# Author: mbinary
# Mail: zhuheqin1@gmail.com
# Blog: https://mbinary.xyz
# Github: https://github.com/mbinary
# Created Time: 2018-05-19  23:07
# Description:
#########################################################################
'''

#!/bin/python3
# notice that  creating   a class's initialization won't conflict with __call__ method
# because the former  call class ,and the latter  call instance

# to be implemented


class polynomial:
    pls = []
    n = 0

    def dictize(pl):
        if isinstance(pl, int) or isinstance(pl, float):
            pl = {0: pl}
        if isinstance(pl, polynomial):
            pl = pl.polynomial.copy()
        return pl

    def isZero(n):
        return abs(n) < 0.000001

    def __init__(self, s='0 0'):
        polynomial.pls.append(self)
        polynomial.n += 1
        if isinstance(s, polynomial):
            self.polynomial = s.polynomial.copy()
            # don't write like this .**self.polynomial = s.polynomial**,it's ref
            return
        elif isinstance(s, dict):
            self.polynomial = s.copy()
            return
        s = s.replace(',', ' ')
        s = s.replace('x', ' ')
        s = s.replace('x^', ' ')
        s = s.replace(':', ' ')
        s = s.replace('\n', ' ')
        s = s.split(' ')
        num = len(s)
        i = 0
        print(s)
        self.polynomial = dict()
        li = [float(i) for i in s]
        while i < num:
            if not polynomial.isZero(li[i]):
                index = li[i+1]
                if index in self.polynomial.keys():
                    self.polynomial[index] += li[i]
                else:
                    self.polynomial[index] = li[i]
            i += 2
        if not self.polynomial:
            self.polynomial = {0: 0}

    def __iter__(self):
        return iter(list(self.polynomial.keys()))

    def __getitem__(self, key):
        return self.polynomial[key]

    def __setitem__(self, key, val):
        self.polynomial[key] = val

    def __delitem__(self, k):
        del self.polynomial[k]

    def __add__(self, pl):
        pl = polynomial.dictize(pl)
        rst = self.polynomial.copy()
        for i in pl:
            if i not in rst:
                rst[i] = pl[i]
            else:
                rst[i] += pl[i]
                if polynomial.isZero(rst[i]):
                    del rst[i]
        return polynomial(rst)

    def __iadd__(self, pl):
        pl = polynomial.dictize(pl)
        for i in pl:
            if i not in self:
                self[i] = pl[i]
            else:
                self[i] += pl[i]
                if polynomial.isZero(self[i]):
                    del self[i]
        return self

    def __sub__(self, pl):
        pl = polynomial.dictize(pl)
        tmp = {i: -j for i, j in pl.items()}
        return self + tmp

    def __mul__(self, pl):
        pl = polynomial.dictize(pl)
        dic = dict()
        for i in pl:
            for j in self:
                index = i+j
                if index in dic:
                    dic[index] += pl[i]*self[j]
                else:
                    dic[index] = pl[i]*self[j]
        return polynomial({i: j for i, j in dic.items() if not polynomial.isZero(j)})

    def __imul__(self, pl):
        self = self*pl
        return self

    def __pow__(self, n):
        rst = polynomial({0: 1})
        for i in range(n):
            rst *= self.polynomial
        return rst

    def __repr__(self):
        return self.__str__()

    def __str__(self):
        output = ''
        if self.polynomial:
            key = sorted(self.polynomial.keys(), reverse=True)
            num = len(key)
            for j, i in enumerate(key):
                if polynomial.isZero(i):
                    output += '%+g' % self[i]
                    continue
                if not polynomial.isZero(self[i]-1):
                    if not polynomial.isZero(self[i]+1):
                        output += "%+g" % self[i]
                    else:
                        output += '-'
                else:
                    output += '+'
                if not polynomial.isZero(i):
                    output += 'x'
                if not polynomial.isZero(i-1):
                    output += '^%g' % i

        if output[0] == '+':
            return output[1:]
        return output

    def iterPolynomial(self, s):
        rst = polynomial({0: 0})
        for i in self:
            rst += s**int(i)*self[i]
        return rst

    def __call__(self, s):
        if isinstance(s, polynomial):
            return self.iterPolynomial(s)
        sum = 0
        for i in self:
            sum += self[i] * s**i
        return sum

    def __xor__(self, n):
        tmp = polynomial(self)
        for i in range(n):
            self = self.iterPolynomial(tmp)
        return self

    def save(self):
        polynomial.pls.append(self)
        polynomial.n += 1

    def delPlynomial(self, n):
        return polynomial.pls.pop(n-1)


def menu():
    print('polynomial operations')
    print('1.create')
    print('2.add')
    print('3.sub')
    print('4.iadd')
    print('5.mul')
    print('6.del')
    print('7.display')
    print('8.cal val')
    print('9.polynomial iter')
    print('10.menu')
    print('11.exit')


if __name__ == '__main__':
    menu()