PAT : 数据结构与算法题目集（中文）7-2 一元多项式的乘法与加法运算

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>

typedef struct linkst *linkstp;

typedef struct linkst
{
    int n;
    int value;
    linkstp p;
} linkst;

int getdigit(void);
void putdigit(int temp);
linkstp getpoly(void);
void printpoly(linkstp sp);
linkstp mulpoly(linkstp, linkstp);
linkstp addpoly(linkstp, linkstp);

int main(int argc, char **argv)
{
    linkstp poly1 = getpoly();
    linkstp poly2 = getpoly();
    linkstp mulans = mulpoly(poly1, poly2);
    printpoly(mulans);
    linkstp addans = addpoly(poly1, poly2);
    printpoly(addans);
    return EXIT_SUCCESS;
}
linkstp addpoly(linkstp a, linkstp b)
{
    if (a->p == NULL)
        return b;
    if (b->p == NULL)
        return a;
    linkstp re = (linkstp)malloc(sizeof(linkst));
    re->p == NULL;
    linkstp ans = re;
    a = a->p;
    b = b->p;
    while (a != NULL && b != NULL)
    {
        if (a->n == b->n)
        {
            if (a-&g