Submission #1180551

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using R=double;

// Combination Table
ll C[51][51]; // C[n][k] -> nCk

void comb_table(int N){ 
	for(int i=0;i<=N;++i){
		for(int j=0;j<=i;++j){
			if(j==0 or j==i){
				C[i][j]=1LL;
			}else{
				C[i][j]=(C[i-1][j-1]+C[i-1][j]);
			}
		}
	}
}

int main(void){
	int N,A,B;
	cin >>  N >> A >> B;

	const int NMAX=50;
	ll v[NMAX];

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

	comb_table(N);
	sort(v,v+N);
	reverse(v,v+N);

	R max_average=0.0;
	for(int i=0;i<A;++i){	
		max_average+=v[i];
	}
	max_average/=A;
	
	int a_th_val_num=0,a_th_val_pos=0;
	for(int i=0;i<N;++i){
		if(v[i]==v[A-1]){
			a_th_val_num++;
			if(i<A){
				a_th_val_pos++;
			}
		}
	}
	
	ll cnt=0LL;
	if(a_th_val_pos==A){
		for(a_th_val_pos=A;a_th_val_pos<=B;++a_th_val_pos){
			cnt+=C[a_th_val_num][a_th_val_pos];
		}
	}else{
		cnt+=C[a_th_val_num][a_th_val_pos];
	}

	cout.precision(20);
	cout << fixed << max_average << endl;
	cout << cnt << endl;
	
	return 0;
}

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