제출 #538546

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
538546		Pichon5	Magneti (COCI21_magneti)	C++17	10 / 110	2 ms	696 KiB

Main

#include <bits/stdc++.h>
#define vi vector<int>
#define pb push_back
#define ll long long
#define F first
#define S second
#define mp make_pair
#define ii pair<int,int>
#define fast ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
const ll MOD=1e9+7;
int n,l,x;
const int tam=10005;
ll fact[50005];
void init(){
   fact[0]=1;
   for(int i=1;i<=50000;i++){
      fact[i]=(fact[i-1]*i)%MOD;
   }
}
ll Pou(int a, int n){
   if(n==0)return 1;
   if(n%2==0){
      ll A=Pou(a,n/2);
      return (A*A)%MOD;
   }else{
      ll A=Pou(a,n/2);
      A=(A*A)%MOD;
      return (A*a)%MOD;
   }
}
ll nck(int n, int k){
   ll res=(fact[n]*Pou((fact[k]*fact[n-k])%MOD,MOD-2))%MOD;
   return res;
}
int main(){
    init();
    cin>>n>>l;
    for(int i=0;i<n;i++){
        cin>>x;
    }
    ll libre=l-(n-1)*x-1;
    if(libre<0){
        cout<<0<<endl;
        return 0;
    }
    cout<<nck(n+libre,n)*fact[n]%MOD<<endl;
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 30
• Subtask 4: 0 / 50