РЮО - С

#include <bits/stdc++.h>
#define ll long long

using namespace std;

int n;
vector<ll> a;
map<ll, int> cnt;
set<ll> b, c;

ll get() {
    ll ans = 0;
    if (c.size() > 0) {
        ll x = -(*c.begin());
        ans = x * x;
    }
    if (b.size() > 1) {
        ll x = -(*b.begin());
        b.erase(-x);
        ll y = -(*b.begin());
        ans = max(ans, x * y);
        b.insert(-x);
    }
    return ans;
}

void update(int k, ll x) {
    if (k >= n) {
        return;
    }
    if (cnt[a[k]] == 2) {
        b.erase(-a[k]);
    } else if (cnt[a[k]] == 4) {
        c.erase(-a[k]);
    }
    cnt[a[k]]--;
    if (cnt[a[k]] == 0) {
        cnt.erase(a[k]);
    }

    a[k] = x;
    cnt[a[k]]++;

    if (cnt[a[k]] == 2) {
        b.insert(-a[k]);
    } else if (cnt[a[k]] == 4) {
        c.insert(-a[k]);
    }
}

int main() {
    cin >> n;
    a.resize(n);

    for (int i = 0; i < n; ++i) {
        cin >> a[i];
        cnt[a[i]]++;
    }

    for (auto e : cnt) {
        ll key = e.first;
        int value = e.second;
        if (value >= 2) {
            b.insert(-key);
        }
        if (value >= 4) {
            c.insert(-key);
        }
    }

    cout << get() << endl;

    int q;
    cin >> q;
    while (q--) {
        int k;
        ll x;
        cin >> k >> x;
        update(k - 1, x);
        cout << get() << endl;
    }

    return 0;
}