polynomial类c++

以下是一个简单的C++ Polynomial类的示例。

#include <iostream>
#include <vector>

using namespace std;

class Polynomial {
private:
    vector<int> coeffs;

public:
    Polynomial() {}

    Polynomial(const vector<int>& c) {
        coeffs = c;
    }

    int degree() const {
        return coeffs.size() - 1;
    }

    int operator[](int i) const {
        if (i >= coeffs.size()) {
            return 0;
        }
        return coeffs[i];
    }

    int& operator[](int i) {
        if (i >= coeffs.size()) {
            coeffs.resize(i+1);
        }
        return coeffs[i];
    }

    Polynomial operator+(const Polynomial& other) const {
        vector<int> res(max(coeffs.size(), other.coeffs.size()));
        for (int i = 0; i < res.size(); i++) {
            res[i] = (*this)[i] + other[i];
        }
        return Polynomial(res);
    }

    Polynomial operator-(const Polynomial& other) const {
        vector<int> res(max(coeffs.size(), other.coeffs.size()));
        for (int i = 0; i < res.size(); i++) {
            res[i] = (*this)[i] - other[i];
        }
        return Polynomial(res);
    }

    Polynomial operator*(const Polynomial& other) const {
        vector<int> res(coeffs.size() + other.coeffs.size() - 1);
        for (int i = 0; i < coeffs.size(); i++) {
            for (int j = 0; j < other.coeffs.size(); j++) {
                res[i+j] += (*this)[i] * other[j];
            }
        }
        return Polynomial(res);
    }

    void print() const {
        for (int i = coeffs.size()-1; i >= 0; i--) {
            if (coeffs[i] != 0) {
                if (i == coeffs.size()-1) {
                    cout << coeffs[i] << "x^" << i;
                } else {
                    cout << " + " << coeffs[i] << "x^" << i;
                }
            }
        }
        cout << endl;
    }
};

int main() {
    vector<int> c1 = {1, 2, 3};
    vector<int> c2 = {4, 5};
    Polynomial p1(c1);
    Polynomial p2(c2);
    Polynomial p3 = p1 + p2;
    Polynomial p4 = p1 * p2;
    p1.print();
    p2.print();
    p3.print();
    p4.print();
    return 0;
}

上述代码实现了一个简单的Polynomial类，支持多项式加减乘，以及输出多项式的功能。