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Submission #1095843

# Submission time Handle Problem Language Result Execution time Memory
1095843 2024-10-03T10:07:28 Z windowwife Žarulje (COI15_zarulje) C++14
100 / 100
 307 ms 37280 KB 
#include<bits/stdc++.h>
#define ll long long
#define task ""
using namespace std;
const int maxn = 1e6 + 2, LG = 20, mod = 1e9 + 7;
ll n, q, f[maxn], invf[maxn], a[maxn], x, t[maxn], res = 1, ans[maxn];
unordered_map<int, int> L, R;
vector<int> stL, stR;
vector<pair<int, int>> changes;
ll power (ll a, ll b)
{
    ll res = 1;
    for (; b > 0; b >>= 1)
    {
        if (b & 1) res = res * a % mod;
        a = a * a % mod;
    }
    return res;
}
void prep ()
{
    f[0] = 1;
    for (int i = 1; i < maxn; i++) f[i] = f[i - 1] * i % mod;
    invf[maxn - 1] = power(f[maxn - 1], mod - 2);
    for (int i = maxn - 2; i >= 0; i--) invf[i] = invf[i + 1] * (i + 1) % mod;
}
ll C (int k, int n)
{
    return f[n] * invf[k] % mod * invf[n - k]%mod;
}
int main()
{
    //freopen(task".INP", "r", stdin);
    //freopen(task".OUT", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    prep();
    cin >> n >> q;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = n; i >= 1; i--)
    {
        while (!stR.empty() && stR.back() > a[i])
        {
            changes.push_back({0, stR.back()});
            res = res * power(C(R[stR.back()], L[stR.back()] + R[stR.back()]), mod - 2) % mod;
            R[stR.back()]--;
            res = res * C(R[stR.back()], L[stR.back()] + R[stR.back()]) % mod;
            stR.pop_back();
        }
        stR.push_back(a[i]);
        changes.push_back({1, a[i]});
        res = res * power(C(R[a[i]], L[a[i]] + R[a[i]]), mod - 2) % mod;
        R[a[i]]++;
        res = res * C(R[a[i]], L[a[i]] + R[a[i]]) % mod;
        t[i] = changes.size();
    }
    for (int i = 1; i <= n; i++)
    {
        while ((int)changes.size() > t[i + 1])
        {
            if (changes.back().first == 0)
            {
                stR.push_back(changes.back().second);
                res = res * power(C(R[stR.back()], L[stR.back()] + R[stR.back()]), mod - 2) % mod;
                R[stR.back()]++;
                res = res * C(R[stR.back()], L[stR.back()] + R[stR.back()]) % mod;
            }
            else
            {
                res = res * power(C(R[stR.back()], L[stR.back()] + R[stR.back()]), mod - 2) % mod;
                R[stR.back()]--;
                res = res * C(R[stR.back()], L[stR.back()] + R[stR.back()]) % mod;
                stR.pop_back();
            }
            changes.pop_back();
        }
        if (i > 1)
        {
            while (!stL.empty() && stL.back() > a[i - 1])
            {
                res = res * power(C(L[stL.back()], L[stL.back()] + R[stL.back()]), mod - 2) % mod;
                L[stL.back()]--;
                res = res * C(L[stL.back()], L[stL.back()] + R[stL.back()]) % mod;
                stL.pop_back();
            }
            stL.push_back(a[i - 1]);
            res = res * power(C(L[a[i - 1]], L[a[i - 1]] + R[a[i - 1]]), mod - 2) % mod;
            L[a[i - 1]]++;
            res = res * C(L[a[i - 1]], L[a[i - 1]] + R[a[i - 1]]) % mod;
        }
        ans[i] = res;
    }
    while (q--)
    {
        cin >> x;
        cout << ans[x] << '\n';
    }
}

Subtask #1
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 15960 KB Output is correct
2 Correct 16 ms 15964 KB Output is correct
3 Correct 16 ms 16220 KB Output is correct
4 Correct 18 ms 16104 KB Output is correct
5 Correct 17 ms 16220 KB Output is correct
6 Correct 19 ms 16216 KB Output is correct

Subtask #2
38.0 / 38.0

# Verdict Execution time Memory Grader output
1 Correct 129 ms 20580 KB Output is correct
2 Correct 227 ms 24516 KB Output is correct
3 Correct 236 ms 24432 KB Output is correct
4 Correct 232 ms 24736 KB Output is correct
5 Correct 241 ms 25472 KB Output is correct
6 Correct 268 ms 33180 KB Output is correct
7 Correct 278 ms 35752 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 15960 KB Output is correct
2 Correct 16 ms 15964 KB Output is correct
3 Correct 16 ms 16220 KB Output is correct
4 Correct 18 ms 16104 KB Output is correct
5 Correct 17 ms 16220 KB Output is correct
6 Correct 19 ms 16216 KB Output is correct
7 Correct 129 ms 20580 KB Output is correct
8 Correct 227 ms 24516 KB Output is correct
9 Correct 236 ms 24432 KB Output is correct
10 Correct 232 ms 24736 KB Output is correct
11 Correct 241 ms 25472 KB Output is correct
12 Correct 268 ms 33180 KB Output is correct
13 Correct 278 ms 35752 KB Output is correct
14 Correct 32 ms 16772 KB Output is correct
15 Correct 133 ms 21952 KB Output is correct
16 Correct 241 ms 27588 KB Output is correct
17 Correct 242 ms 26052 KB Output is correct
18 Correct 262 ms 28088 KB Output is correct
19 Correct 263 ms 26808 KB Output is correct
20 Correct 298 ms 34716 KB Output is correct
21 Correct 307 ms 37280 KB Output is correct