Submission #1650295

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Source Code Expand

//
// Created by Akifumi Ohata on 2017/10/04.
//


#include<iostream>
#include <vector>
#include <numeric>
#include <math.h>
#include <cmath>
#include <algorithm>
#include <iomanip>

using namespace std;

using ll =  long long int;

int main() {
    ios::sync_with_stdio(false);

    int N, M;

    ll MOD=1000000007;


    cin >> N ;

    std::vector<int> RankArrays(N,0);

    for(int i=0;i<N ;i++){

        int tmp;
        cin >> tmp;
        RankArrays[tmp]++;
    }


    std::vector<ll> AnsArray(N,0);

    AnsArray[0]=1;

    int k=0;

    for(k=0;k<N;k++){

        int ranknum = RankArrays[k];

        if(k==0){
            if(ranknum!=1){
                cout<< 0 << endl;
                return 0;
            }
            continue;
        }else{
            if(ranknum==0){
                goto END;
            }
        }

        ll C=(static_cast<ll>(pow(2, RankArrays[k - 1]) -1))%MOD;

        ll A= (static_cast<ll>(pow(C, RankArrays[k])))%MOD;

        ll B= (static_cast<ll>(pow(2, (RankArrays[k] - 1)*RankArrays[k]/2)))%MOD;
        AnsArray[k]=(AnsArray[k-1]*A*B)%MOD;



    }

    END:


/*    for(const auto &p : AnsArray){

        cout<< p << endl;
    }*/

    cout  << AnsArray[k-1] << endl ;

    return 0;
}

Submission Info

Judge Result