怎么不行！！！！！ 小白求大佬帮助

#include <iostream>
using namespace std;
int main() {
	double a = 0;
	int t = 0;
	int arr[10000] = { 0 };
	int n = 0;
	int f = 0;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> a >> t;
		for (int j = 1; j <=t; j++) {
			f = (int)(a * j);
			arr[f]++;
		}
	}
	int len = sizeof(arr) / sizeof(arr[1]);
	for (int i = 1; i <= len; i++) {
		if (arr[i] % 2 != 0) {
			cout << i << endl;
		}
	}
	return 0;
}