PTA 1030 完美数列 (25 分)

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int main()
{
	long long n, p, tmp = 0, final = 0;
	cin >> n >> p;
	vector<int>v(n);
	for (int i = 0; i < n; i++) {
		cin >> v[i];
	}
	sort(v.begin(), v.end());
	for (int i = 0; i < n; i++) {
		for (int j = i + final; j < n; j++) {
			if (v[j] <= p * v[i]) {
				tmp = j - i + 1;
				if (tmp > final)final = tmp;
			}
			else break;
		}
	}
	cout << final;
	return 0;
}

这个题运用了two pointers的思想。
参考：https://blog.youkuaiyun.com/pushup8/article/details/85071735