Submission #1131234

---

Source Code Expand

#include <iostream>
#include <iomanip>
#include <string>
#include <algorithm>
#include <vector>
#include <map>

using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;
const int MAXN = 100100;

int N;
int arr[MAXN];
int aval[MAXN];

int main()
{
    cin >> N;
    for (int i = 0; i < N; i++)
        cin >> arr[i];

    aval[0] = 1;
    int codd = 1;
    for (int i = 1; i < N; i++)
    {
        if (arr[i-1] >= codd)
        {
            aval[i] = aval[i-1];
            codd += 2;
        }
        else
        {
            aval[i] = aval[i-1] + 1;
        }
    }

    ll ans = 1;
    int cloc = 0;
    for (int i = 1; i <= N; i++)
    {
        while (cloc < N && aval[cloc] == i)
            cloc++;
        ans = (ans * (cloc - i + 1)) % MOD;
    }

    cout << ans << "\n";
}

Submission Info

Judge Result