結果

問題 No.243 出席番号(2)
ユーザー heno239
提出日時 2020-08-15 23:58:16
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 40 ms / 2,000 ms
コード長 2,975 bytes
コンパイル時間 1,185 ms
コンパイル使用メモリ 121,136 KB
実行使用メモリ 6,820 KB
最終ジャッジ日時 2024-10-11 03:58:58
合計ジャッジ時間 2,495 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge5
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 30
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
using namespace std;
//#define int long long
typedef long long ll;
typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);
ll mod_pow(ll x, ll n, ll m = mod) {
    ll res = 1;
    while (n) {
        if (n & 1)res = res * x % m;
        x = x * x % m; n >>= 1;
    }
    return res;
}
struct modint {
    ll n;
    modint() :n(0) { ; }
    modint(ll m) :n(m) {
        if (n >= mod)n %= mod;
        else if (n < 0)n = (n % mod + mod) % mod;
    }
    operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, ll n) {
    if (n == 0)return modint(1);
    modint res = (a * a) ^ (n / 2);
    if (n % 2)res = res * a;
    return res;
}
ll inv(ll a, ll p) {
    return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
ll gcd(ll a, ll b) {
    if (a < b)swap(a, b);
    while (b) {
        ll r = a % b; a = b; b = r;
    }
    return a;
}
modint dp[5001];
void solve() {
    int n; cin >> n;
    vector<int> a(n);
    rep(i, n) {
        cin >> a[i];
    }
    sort(all(a));
    vector<int> b;
    rep(i, n) {
        int cnt = 1;
        while (i + 1 < n && a[i] == a[i + 1]) {
            i++; cnt++;
        }
        if(a[i]<=n-1)b.push_back(cnt);
    }
    dp[0] = 1;
    rep(i, b.size()) {
        per(j, n) {
            dp[j + 1] += dp[j] * (modint)b[i];
        }
    }
    vector<modint> fact(n + 1);
    fact[0] = 1;
    rep1(i, n) {
        fact[i] = fact[i - 1] * (modint)i;
    }
    modint ans = 0;
    rep(i, n + 1) {
        modint num = fact[n - i] * dp[i];
        if (i % 2 == 0)ans += num;
        else ans -= num;
    }
    cout << ans << "\n";
}
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    //cout << fixed << setprecision(15);
    //init_f();
    //init();
    //expr();
    //int t; cin >> t; rep(i, t)
    solve();
    return 0;
}
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