Submission #862624

#	Time	Username	Problem	Language	Result	Execution time	Memory
862624		AbdelmagedNour	Magneti (COCI21_magneti)	C++17	110 / 110	42 ms	4960 KiB

Main

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
typedef long long ll;
const int N=12005,mod=(1e9)+7;
ll Fact[N],inv[N];
void preprocess(){
    Fact[0]=Fact[1]=inv[0]=inv[1]=1;
    for(int i=2;i<N;i++){
        Fact[i]=i*Fact[i-1]%mod;
        inv[i]=mod-mod/i*inv[mod%i]%mod;
    }
    for(int i=2;i<N;i++)inv[i]=inv[i]*inv[i-1]%mod;
}
ll nCr(int n,int r){
    return Fact[n]*inv[n-r]%mod*inv[r]%mod;
}
ll dp[N][55];
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
    preprocess();
	int n,l;
	cin>>n>>l;
    int a[n+1]={};
	for(int i=1;i<=n;i++)cin>>a[i];
    sort(a+1,a+n+1);
    dp[0][0]=1;
    for(int i=1;i<=n;i++){
        for(int k=l;k>=1;k--){
            for(int j=1;j<=i;j++){
                dp[k][j]=dp[k-1][j-1];
                if(k>=a[i])dp[k][j]+=dp[k-a[i]][j]*2LL*j;
                if(k>=(2*a[i]-1))dp[k][j]+=dp[k-(2*a[i]-1)][j+1]*j*(j+1);
                dp[k][j]%=mod;
            }
        }
        dp[0][0]=0;
    }
    ll res=0;
    for(int i=1;i<=l;i++)res+=dp[i][1]*nCr(n+l-i,n)%mod;
    cout<<(res%mod);
	return 0;
}

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