多项式加法

前些日子面试,让写个多项式加法,写了半天也有bug,我觉得很丢脸,要多多练习写代码

    多项式加法 是按照序数从高到低排序,并且指数前面参数不能小于0(自己设定的)

    typedef struct node{
    int value;
    int n;
    struct node* next;
}linknode;

linknode* add(linknode* A,linknode* B)
{

    if(A == NULL) return B;
    if(B == NULL) return A;

    linknode* preA = A;
    linknode* tmpA = A;
    linknode* tmpB = B;

    while(tmpA != NULL && tmpB != NULL) {
        if(tmpA->n > tmpB->n) {
            if(preA != A)
                preA->next = tmpA;
            preA = tmpA;
            tmpA = preA->next;

        } else if(tmpA->n == tmpB->n) {
            //maybe overflow

            linknode* p = tmpA;
            if(preA != A)
                preA->next = tmpA;
            tmpA->value += tmpB->value;
            preA = tmpA;
            tmpA = tmpA->next;

            p = tmpB ;
            tmpB = tmpB->next;
            free(p);
            p = NULL;


        } else if(tmpA->n < tmpB->n) {
            if(preA != A)
                preA->next = tmpB;
            preA = tmpB;
            tmpB = tmpB->next;
        }
    }
    if(tmpB != NULL) {
        preA->next = tmpB;
    }
    return A;
}