제출 #782949

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
782949		makanhulia	The Xana coup (BOI21_xanadu)	C++17	0 / 100	2 ms	488 KiB

xanadu

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n,m;
ll a[2005],b[2005];
ll pref[2005],suff[2005];
ll mod=1e9+7;
ll jawab;
vector <ll> ans;
ll fact (ll n){
    if (n==0) return 1;
    return n%mod*fact(n-1)%mod;
}
ll kali (ll a, ll b){
    return (a*b)%mod;
}
ll simpan=1;
void fexpo(ll a, ll b){
    // cout<<a<<" "<<b<<endl;
    if (b==1) {
        simpan=kali(simpan,a);
        return;
    }
    if (b%2==0){
        fexpo(kali(a,a),b/2);
    }
    else{
        simpan=kali(simpan,a);
        fexpo(kali(a,a),(b-1)/2);
    }
}
int main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin>>n>>m;
    for (int i=1;i<=n;i++){
        cin>>a[i];
        pref[i]=max(pref[i-1],a[i]);
        // cout<<pref[i]<<endl;
    }
    for (int i=1;i<=n;i++){
        suff[i]=max(suff[i-1],a[n-i+1]);
    }
    // for (int i=1;i<=n;i++) cout<<pref[i]<<" "<<suff[i]<<":::"<<i<<endl;
    for (int i=1;i<=m;i++){
        cin>>b[i];
    }
    if (n<m) {
            cout<<0;
            return 0;
        }
        ll tes=1;
        ll u=m-1;
        fexpo(fact(u)%mod,mod-2);
        tes*=simpan%mod;
        simpan=1;
        fexpo(fact(n-m-2)%mod,mod-2);
        tes*=simpan%mod*fact(n-1)%mod;
        tes%=mod;
        cout<<tes;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 40
• Subtask 5: 0 / 30