1002 A+B for Polynomials

PAT甲级真题练习1002

题目链接：https://pintia.cn/problem-sets/994805342720868352/problems/994805526272000000

主要注意几个特殊的测试case

1、输入的数据中含有未合并的多项式，例如

3 2 1.2 2 2.3 1 1.4

2 3 0.1 1 1.1

2、如果底数相加之后为0，则这组数据就应该丢弃，例如

input

1 2 1.2

1 2 -1.2

output

0

本人测试通过的代码：

#include <iostream>
#include <string>
#include <map>
#include <iomanip>

using namespace std;

int main()
{
    int k;
    constexpr int line = 2;
    map<int, double> out;
    int exp;
    double coe;

    for (int i = 0; i < line; i++) {
        cin >> k;
        for (int j = 0; j < k; j++) {
            cin >> exp >> coe;
            auto p = out.find(exp);
            if (p == out.end()) {
                out.insert({ exp,coe });
            }
            else {//相同指数
                p->second += coe;
                if (p->second == 0) {//底数为零的情况
                    out.erase(exp);
                }
            }
        }
    }

    cout << out.size();
    for (auto i = out.rbegin(); i != out.rend(); i++) {
        cout << ' ' << i->first << ' ' << fixed << setprecision(1) << i->second;
    }
    cout << endl;
}