Submission #1410562

---

Source Code Expand

#include<iostream>
#include<utility>
#include<tuple>
#include<set>
#include<list>
#include<vector>
#include<map>
#include<algorithm>
#include<queue>
#include<math.h>

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FUNCTION__ << endl;
#define int long long

const long long MAXN = 100;
const long long MOD = 1e9+7;
const long long INF = __LONG_LONG_MAX__ / 2;

using namespace std;

int hoge[MAXN];

constexpr int power(int b, int i){
  if (i == 1) return b % MOD;
  if (i % 2 == 0) {
    return power(b*b % MOD, i/2) ;
  } else {
    return power(b*b % MOD, i/2)*b % MOD ;
  }
}

constexpr int factseed(int n){
  if (n == 0 ) return 1;
  return (n * (factseed(n-1))) % MOD;
}

constexpr int invMod(int n){
  return power(n,MOD - 2);
}


template<int N>
struct Facts {
    constexpr Facts() : arr() {
        for (auto i = 0; i != N; ++i){
            arr[i] = factseed(i); 
        }
    }
    int arr[N];
};

constexpr auto facts = Facts<MAXN>();
constexpr int fact(int n){
  return facts.arr[n];
}

template<int N>
struct Finv {
    constexpr Finv() : arr() {
        for (auto i = 0; i != N; ++i){
            arr[i] = invMod(fact(i)); 
        }
    }
    int arr[N];
};

constexpr auto finvs = Finv<MAXN>();

int combination(int m, int n){
  if(m<0 || n < 0 || m < n) return 0;
  return (((fact(m)*invMod(fact(n))) % MOD) * invMod(fact(m-n))) % MOD;
}

int perm(int m,int n){
  if (n == 0) return 1;
  return m * (perm (m-1, n-1));
}

signed main(){
    int N, P;
    cin >> N >> P;
    int even_counts = 0;
    int odd_counts = 0;
    for (int i = 0; i < N; i++){
      int a;
      cin >> a;
      if (a % 2 == 0){
       even_counts++;
      }
    }
    odd_counts = N - even_counts;
    if (P == 0){// must be even
      int prod = 0;
      for(int i = 0; i<= odd_counts  ; i += 2){
        prod += combination(odd_counts, i);
      }
      printf("%lld\n",prod *(int)pow(2, even_counts));
    } else {
      int prod = 0;
      for(int i = 1; i<= odd_counts ; i += 2){
        prod += combination(odd_counts, i);
      }
      printf("%lld\n",prod *(int)pow(2, even_counts ));
    }
    return 0;
}

Submission Info

Judge Result