浙大PAT甲级-1002

这道题是大一的时候就做过的，当时刚学运算符重载。现在我用的是链表来做的，也算是复习一下快忘光的数据结构吧。

#include <iostream>#include<iomanip>using namespace std;//节点（多项式的项）struct listNode{int exp;double coe;listNode *link;listNode(){}listNode(int e, double c){exp = e;coe = c;link = NULL;}};class list{public:listNode *first;listNode *last;   //方便后面直接用就没设为private啦list(){first = NULL;last = NULL;}//输入，初始化链表void init(int n){int e;double c;for (int i = 0; i<n; i++){cin >> e >> c;insert(e, c);}}    //插入节点void insert(int e, double c){listNode *newNode = new listNode(e,c);if (first == NULL){newNode->link = first;first =  newNode;last = newNode;}else{last->link = newNode;last = newNode;}last->link = NULL;}//将系数为0的节点都剪掉void merge(){while (first!=NULL && first->coe == 0){first = first->link;}if (first != NULL){listNode *m = first->link;listNode *n = first;while (m != NULL){if (m->coe == 0){n->link = m->link;}else{n = n->link;}m = m->link;}}}//链表长度int Length(){listNode *p = first;int cnt = 0;while (p != NULL){p = p->link;cnt++;}return cnt;}};int main(){int p, q;while (cin >> p){list a, b, c;a.init(p);cin >> q;b.init(q);//多项式加法listNode *ca = a.first;listNode *cb = b.first;while (ca != NULL&&cb != NULL){if (ca->exp > cb->exp){c.insert(ca->exp, ca->coe);ca = ca->link;}else if (ca->exp == cb->exp){c.insert(ca->exp, ca->coe + cb->coe);ca = ca->link;cb = cb->link;}else{c.insert(cb->exp, cb->coe);cb = cb->link;}}if (ca != NULL){while (ca != NULL){c.insert(ca->exp, ca->coe);ca = ca->link;}}else if (cb != NULL){while (cb != NULL){c.insert(cb->exp, cb->coe);cb = cb->link;}}c.merge();cout << c.Length();listNode *m = c.first;while (m != NULL){cout << " " << m->exp << " " << setiosflags(ios::fixed)<< setprecision(1) << m->coe;//输出是有精度要求的哦m = m->link;}cout << endl;}return 0;}