Submission #1244135

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Source Code Expand

#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <algorithm>
#include <sstream>
#include <cmath>
#include <set>
#include <iomanip>
#include <deque>
#include <stdio.h>
#include <fstream>
using namespace std;

#define REP(i,n) for(int (i)=0;(i)<(int)(n);(i)++)
#define RREP(i,n) for(int (i)=(int)(n)-1;i>=0;i--)
#define REMOVE(Itr,n) (Itr).erase(remove((Itr).begin(),(Itr).end(),n),(Itr).end())
#define UNIQUE(Itr) sort((Itr).begin(),(Itr).end()); (Itr).erase(unique((Itr).begin(),(Itr).end()),(Itr).end())
#define LBOUND(Itr,val) lower_bound((Itr).begin(),(Itr).end(),(val))
#define UBOUND(Itr,val) upper_bound((Itr).begin(),(Itr).end(),(val))
typedef long long ll;

ll N,A,B;
vector<double> v;

#define MOD 1000000000000000000

ll extgcd(ll a, ll b, ll& x, ll& y) {
    if(b==0){
        x=(a>=0)?1:-1;
        y=0;
        return abs(a);
    }else{
        ll res=extgcd(b,a%b,y,x);
        y-=(a/b)*x;
        return res;
    }
}

ll mod_inverse(ll a, ll m) {
    ll x,y;
    extgcd(a,m,x,y);
    return (m+x%m)%m;
}

ll c(ll n, ll k) {
    ll res=1;
    for(int i=0;i<k;i++)res=(res*((n-i)%MOD))%MOD;
    for(int i=1;i<=k;i++)res=(res*mod_inverse(i,MOD))%MOD;
    return res;
}

int main() {
    
    cin >> N >> A >> B;
    v.resize(N);
    REP(i,N) cin >> v[i];
    
    sort(v.begin(),v.end());
    reverse(v.begin(),v.end());
    
    double ave = 0.0;
    double sum = 0.0;
    int cnt = -1;
    REP(i,B) {
        if(i<A-1) sum += v[i];
        else {
            sum += v[i];
            double avet = sum / ((double)(i + 1));
            if(ave <= avet) {
                ave = avet;
                cnt = i+1;
            }
        }
    }
    
    cout << fixed << setprecision(10) << ave << endl;
    
    map<double,int> cntm;
    REP(i,cnt) cntm[v[i]]++;
    
    ll ko = cntm[ave];
    ll s = cnt - A;
    
    ll ans = 0;
    for(ll i=0;i<=s;i++){
        ans += c(ko,i);
    }
    
    cout << ans << endl;
    
    return 0;
}

Submission Info

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