注意10^9 * 10^9会整形溢出，所以队列存的数不能int类型，得是long long类型；

#include<iostream>
#include<queue>
#include<algorithm>
#include<vector>
using namespace std;
int ans = -1;
queue<long long> ansque;
int n;
vector<int> tempvec;
int p;
int main() {
    cin >> n >> p;
    if (n == 0||p==0) {
        cout << 0;
        return 0;
    }
    for (int i = 0; i < n; i++)
    {
        int temp;
        cin >> temp;
        tempvec.push_back(temp);
    }
    sort(tempvec.begin(), tempvec.end());
    ansque.push(tempvec[0]);
    ans = 1;
    for (int i = 1; i < tempvec.size(); i++)
    {
        if (ansque.front()*p >= tempvec[i]) {
            ansque.push(tempvec[i]);
        }
        else
        {
            while (!ansque.empty() && ansque.front()*p <= tempvec[i]) {
                ansque.pop();
            }
            ansque.push(tempvec[i]);
        }
        if (ansque.size() > ans) {
            ans = ansque.size();
        }
    }
    cout << ans;
    return 0;
}

不借助队列，简洁版本

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