1085 Perfect Sequence--双指针

#include<bits/stdc++.h>
using namespace std;
#define ll long long
int main(){
    ll n,p;
    cin>>n>>p;
    ll a[n];
    for(ll i=0;i<n;i++){
        cin>>a[i];
    }
    sort(a,a+n);
    ll ans=0;
    for(ll i=0,j=0;i<n;i++){
        while(j<n&&a[i]>a[j]*p){
            j++;
        }
        ans=max(ans,i-j+1);
    }
    cout<<ans;
}