用cpp语言设计一个多项式相加的程序,要求写出完整的代码,对多项式进行的第一个操作是对数据项中的变量排序,输入多项式之后,每个数据项都分别用排序向量进行排序,链表中的节点可以对该向量进行访问.第二个操作是多项式相加.这个过程是由创建一个链表开始的,这个链表是由待相加的多项式的节点副本组成的.通过这种方式,两个多项式都不会受到影响,并且可以在其他操作中使用.

以下是用 C++ 实现多项式相加的代码示例：

#include <iostream>
#include <algorithm>
#include <vector>
#include <utility>
#include <unordered_map>

using namespace std;

struct Node {
  vector<int> coeffs;
  int degree;
  Node *next;
  Node(vector<int> coeffs, int degree) : coeffs(coeffs), degree(degree), next(nullptr) {}
};

// 根据指数从大到小排序
bool compare(const Node &n1, const Node &n2) {
  return n1.degree > n2.degree;
}

// 将节点插入链表
void insert(Node *&head, Node *node) {
  if (!head) {
    head = node;
    return;
  }
  if (head->degree < node->degree) {
    node->next = head;
    head = node;
    return;
  }
  Node *curr = head;
  while (curr->next && curr->next->degree >= node->degree) {
    curr = curr->next;
  }
  node->next = curr->next;
  curr->next = node;
}

// 将链表中的节点复制到另一个链表中
void copy(Node *&dst, Node *src) {
  while (src) {
    Node *node = new Node(src->coeffs, src->degree);
    insert(dst, node);
    src = src->next;
  }
}

// 将两个多项式相加，返回相加后的多项式
Node *add(Node *poly1, Node *poly2) {
  Node *result = nullptr;
  Node *curr1 = poly1, *curr2 = poly2;
  while (curr1 && curr2) {
    if (curr1->degree == curr2->degree) {
      // 将两个多项式的系数相加
      vector<int> coeffs;
      for (int i = 0; i < curr1->coeffs.size(); i++) {
        coeffs.push_back(curr1->coeffs[i] + curr2->coeffs[i]);
      }
      Node *node = new Node(coeffs, curr1->degree);
      insert(result, node);
      curr1 = curr1->next;
      curr2 = curr2->next;
    } else if (curr1->degree > curr2->degree) {
      insert(result, new Node(curr1->coeffs, curr1->degree));
      curr1