【PAT甲级】1002 A+B for Polynomials (25 分)

#include<iostream>
#include<iomanip>
using namespace std;
int main() {
	float array_1[1001], array_2[1001], array[1001];
	int mark_1[1001], mark_2[1001], mark[1001];
	int count1, count2, count = 0;
	for (int i = 0; i < 1001; i++) {
		mark_1[i] = 0;
		mark_2[i] = 0;
		array_1[i] = 0;
		array_2[i] = 0;
	}
	cin >> count1;
	for (int i = 0; i < count1; i++) {
		int n;
		cin >> n;
		mark_1[n] = 1;
		cin >> array_1[n];
	}
	cin >> count2;
	for (int i = 0; i < count2; i++) {
		int n;
		cin >> n;
		mark_2[n] = 1;
		cin >> array_2[n];
	}
	for (int i = 0; i < 1001; i++) {
		mark[i] = mark_1[i] + mark_2[i];
		array[i] = array_1[i] + array_2[i];
		if (mark[i] != 0 && array[i] != 0) count++;
	}
	int first = 0;
	while (mark[first] == 0 || array[first] == 0) {
		first++;
		if (first > 1000) {
			cout << 0;
			return 0;
		}//项数为0的情况
	}
	cout << count << " ";
	for (int i = 1000; i > first; i--) {
		if (mark[i] != 0 && array[i] != 0) {
			cout << i << " ";
			cout << fixed << setprecision(1) << array[i] << " ";//格式化输出 控制一位小数
		}
	}
	cout << first << " " << fixed << setprecision(1) << array[first];
	system("pause");
	return 0;
}

注意点：1. 输出控制一位小数   2. 注意正负相抵为0的情况   3.注意最终项数为0的情况

待改进：无需多mark数组，下次再改...