两个一元多项式相加（链表 || 顺序表实现）

顺序表实现：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <map>
using namespace std;
#define maxsize 1000
struct Data
{
    double coef;
	int exp;
};
struct List
{
	Data* elem;
	int length;
};
char s[100];
map <int, int> m;
bool cmp(Data a, Data  b)
{
	return a.exp < b.exp;
}
void InitList(List &L)
{
    L.elem = (Data* )new Data[maxsize];
    L.length = 0;
}
void Derivative(int len, List L)
{
    int n = 1,flag = 0;
    for(int i = 0;i < len;i ++)
    {
        double coef = L.elem[i].coef;
        int exp = L.elem[i].exp;
         if(exp == 0)
        {
            coef = 0;
        }
        else
        {
            coef *= exp;
            exp --;
        }
         if(fabs(coef) < 1e-6)
            continue;
         else
         {
            flag = 1;
            if(n != 1 && coef > 0)
                printf("+");
            if(exp == 0)
                printf("%g", coef);
            else if(coef!= 1 && exp != 0 && coef != -1)
            {
                if(exp == 1)
                    printf("%gx",coef);
                else
                    printf("%gx^%d",coef, exp);
            }
            else if(coef == 1)
            {
                if(exp == 1)
                    printf("x");
                else
                    printf("x^%d",exp);
            }
            else if(coef == -1)
            {
                if(exp == 1)
                    printf("-x");
                else
                    printf("-x^%d",exp);
            }
            n ++;
        }
    }
    if(!flag) printf("0");
    printf("\n");
}
int main()
{
	freopen("in.txt", "r", stdin);
	List L;
	int op1 = 1, op2 = 1,op3 = 1,op4 = 1;
	double a;
	int b, cases = 1,flag;
	while(scanf("%s", s) != EOF)
	{
        printf("Case %d:\n",cases++);
        InitList(L);
		op1 = op2 = op3 = op4 = 1;
		flag = 0;
		int len = strlen(s);
		for(int i = -10000;i <= 10000;i ++)
			m[i] = -1;
		int k = 0;
		for(int i = 0;i < len;i ++)
		{
            a = 0;
			b = 0;
			op1 = op2 = 1;
			if(s[0] == '-' && i == 0)
            {
                op4 = -1;
                i ++;
            }
            if(s[i+1] == '(')
            {
                Derivative(k, L);
                flag = 1;
            }
			if(s[i] == '=') break;
			if(s[i] == '(') continue;
			if(s[i] == ')')
			{

				i ++;
				op4 = 1;
				if(s[i] == '=')
                {
					 if(!flag)
                        Derivative(k, L);
                     break;
                }
				else
				{
                    flag = 1;
					Derivative(k, L);
					if(s[i] == '+')
						op3 = 1;
					else if(s[i] == '-')
						op3 = -1;

				}
			}
            if(s[i] == '-')
			{

				i ++;
				op1 = -1;
			}
			else if(s[i] == '+')
			{
				i ++;
				op1 = 1;
			}
			if(s[i] >= '0' && s[i] <= '9')
			{
				while(s[i] >= '0' && s[i] <= '9' && i < len)
				{
					a = a*10+(s[i]-'0');
					i ++;
				}
				if(s[i] == '.')
				{
					i ++;
					double x = 0.1;
					while(s[i] >= '0' && s[i] <= '9' && i < len)
					{
						a += x*(s[i]-'0');
						i ++;
						x *= 0.1;
					}
				}
				a = a*op1*op3*op4;
			}
			else if(s[i] == 'x')
			{
				a = op1*op3*op4;
			}
			if(s[i] == 'x')
			{
				i ++;
				if(s[i] == '^')
				{
					i ++;
					if(s[i] == '-')
					{
						op2 = -1;
						i ++;
					}