PAT 1002. A+B for Polynomials (25)

题目地址： http://www.patest.cn/contests/pat-a-practise/1002

这个题我能说我交了无数次吗？ 坑， 系数是0 不能输出

 1 #include<iostream>

 2 #include<iomanip>

 3 #include<map>

 4 

 5 using namespace std;

 6 

 7 const double eps = 1e-9;

 8 int main() {

 9         int k;

10         while(cin >> k) {

11                 map<int, double> p;

12                 int e; 

13                 double a;

14                 for (int i = 0; i < k; ++i) {

15                         cin >> e >> a;

16                         p[e] = a;

17                 }

18                 cin >> k;

19                 for (int i = 0; i < k; ++i) {

20                         cin >> e >> a;

21                         if (p.count(e)) {

22                                 double x = p[e];

23                                 if (!(x + a > -eps && x + a < eps)) {

24                                         p[e] += a;

25                                 } else {

26                                         p.erase(e);

27                                 }

28                         } else {

29                                 p[e] = a;

30                         }

31                 }

32                 cout << p.size();

33                 for (map<int, double>::reverse_iterator iter = p.rbegin(); iter != p.rend(); ++iter) {

34                         cout << " " << iter->first << " ";

35                         cout << fixed << setprecision(1) << iter->second; 

36                 }

37         }

38         return 0;

39 }