Submission #7805014

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Source Code Expand

#include "bits/stdc++.h"

using namespace std;

void solve()
{
    long n, k;
    cin >> n >> k;
    vector<long> as(n);
    vector<long> fs, cnt;
    for (long f = 1; f * f <= k; f++)
    {
        if (k % f == 0)
        {
            fs.push_back(f);
            if (f * f != k)
            {
                fs.push_back(k / f);
            }
        }
    }
    int m = fs.size();
    cnt.resize(m);
    sort(fs.begin(), fs.end());
    for (int i = 0; i < n; i++)
    {
        cin >> as[i];
        for (int j = 0; j < m; j++)
        {
            if (as[i] % fs[j] == 0)
            {
                cnt[j]++;
            }
        }
    }
    long ans = 0;
    for (auto x : as)
    {
        long y = k / x;
        int i = distance(fs.begin(), lower_bound(fs.begin(), fs.end(), y));
        ans += cnt[i] - (x % y == 0);
    }
    cout << ans / 2 << endl;
}

int main()
{
    solve();
    return 0;
}

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