70pts求助

#include <bits/stdc++.h>
#define __init ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define int long long

using namespace std;

int n, m, ans;
unordered_map<int, int> f;

signed main() {
    __init;
    int tmp;
    cin >> n;
    while(n--) {
        cin >> tmp;
        f[tmp]++, m = max(m, tmp);
    }
    for(pair<int, int> i:f) {
        for(int j = 2*i.first;j <= m;j+=i.first)
            ans += i.second * f[j];
        ans += i.second * (i.second-1);
    }
    cout << ans;
    return 0;
}