Codeforces Round #Pi (Div. 2) C

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<algorithm>
#include<map>
#include<set>
#include<vector>
#include<queue>
#include<stack>
//#include<bits/std c++.h>
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
const LL MOD = 1e7 + 7;
const LL maxn = 1e5 + 131;
map<LL,LL> Num1;
map<LL,LL> Num2;
LL Line[maxn<<1];
LL N,K;
int main()
{
    while(cin >> N >> K)
    {
        LL Sum = 0;
        Num1.clear(); Num2.clear();
        for(int i = 1; i <= N; ++i)
            cin >> Line[i], Num1[Line[i]] ++;
        for(int i = N; i >= 1; --i)
        {
            Num2[Line[i]]++;
            if(i == 1 || i == N )continue;
            if(Num2.count(Line[i] * K) && !(Line[i] % K))
            {
                LL L,R;
                if(Line[i] == Line[i]* K) R = Num2[Line[i]*K] - 1;
                else R = Num2[Line[i]*K];
                L = Num1[Line[i] / K] - Num2[Line[i] / K];
                Sum += (L * R);
            }
        }
        cout << Sum << endl;
    }
}