Submission #3836967

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Source Code Expand

#include <iostream>
#include <math.h>
#include <vector>
#include <stack>
#include <cstdio>
#include <string>
#include <bitset>
#include <list>
#include <set>
#include <algorithm>
#include <numeric>
#include <unordered_map>
#include <functional>
#include <queue>
#include <regex>
#include <cassert>
#include <map>
#include <type_traits>
#include <array>
#include <cassert>
#include <typeinfo>

// #include "bits/stdc++.h"

using namespace std;



namespace {
#define rep(i, N, M) for(ll i=N, i##_len=(M); i<i##_len; ++i)
#define rep_skip(i, N, M, ...) for(ll i=N, i##_len=(M); i<i##_len; i+=(skip))
#define rrep(i, N, M)  for(ll i=(M)-1, i##_len=(N-1); i>i##_len; --i)
#define pb push_back

	typedef pair<double, double> pd;

	typedef long long ll;
	typedef unsigned long long ull;
	typedef pair<ll, ll> pll;
	typedef tuple<ll, ll, ll> tll;
	typedef tuple<ll, ll, ll, ll> tll4;
	typedef tuple<ll, ll, ll, ll, ll> tll5;
	typedef tuple<ll, ll, ll, ll, ll, ll> tll6;

	typedef vector<ll> vll;
	typedef vector<vll> vvll;
	typedef vector<pll> vpll;
	typedef vector<bool> vb;
	typedef vector<vb> vvb;
	typedef vector<string> vs;
	template<typename T>
	using pq_greater = priority_queue<T, vector<T>, greater<T>>;

#define all(a)  (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define vec(a) vector<a>
#define perm(c) sort(all(c));for(bool c##perm=1;c##perm;c##perm=next_permutation(all(c)))


	template<class T, class S>
	T atbit(T n, S i) {
		return (n >> i) % 2;
	}

	template<class T>
	T getbit(T i) {
		return 1LL << i;
	}

	constexpr ll POW(ll n, ll m) {
		ll res = 1;
		rep(i, 0, m) {
			res *= n;
		}
		return res;
	}

	vll getDivisors(ll n) {
		vll res;
		ll i = 1;

		for (; i*i < n; i++) {
			if (n%i == 0) {
				res.push_back(i);
				res.push_back(n / i);
			}
		}
		if (i*i == n)res.push_back(i);
		sort(res.begin(), res.end());
		return res;
	}

	vll getDivisors(ll n, ll m) {
		if (n > m) swap(n, m);
		vll res;
		ll i = 1;

		for (; i*i < n; i++) {
			if (n%i == 0) {
				if (m%i == 0) res.push_back(i);
				if (m % (n / i) == 0) res.push_back(n / i);
			}
		}
		if (i*i == n) if (m%i == 0) res.push_back(i);
		sort(res.begin(), res.end());
		return res;
	}


	ll gcd(ll a, ll b) {
		if (a%b == 0) return b;
		else return gcd(b, a%b);
	}

	template<
		typename Inputs,
		typename Functor,
		typename T = typename Inputs::value_type>
		void sort_by(Inputs& inputs, Functor f) {
		std::sort(std::begin(inputs), std::end(inputs),
			[&f](const T& lhs, const T& rhs) { return f(lhs) < f(rhs); });
	}

	template<int I>
	vll proj(vpll v) {
		vll res(v.size());
		rep(i, 0, v.size()) {
			if (!I) res[i] = v[i].first;
			else res[i] = v[i].second;
		}
		return res;
	}


	template<int I, class T>
	vll proj(T v) {
		vll res(v.size());
		rep(i, 0, v.size()) {
			res[i] = get<I>(v[i]);
		}
		return res;
	}
	vector<pll >prime_factorize(ll n) {
		vector<pll> res;
		for (ll p = 2; p*p <= n; ++p) {
			if (n%p != 0)continue;
			ll num = 0;
			while (n%p == 0) { ++num; n /= p; }
			res.push_back({ p,num });
		}
		if (n != 1) res.push_back(make_pair(n, 1));
		return res;
	}

}

ll MOD = 1000000007;
ll INF = 1LL << 60;
ll n;

ll MAX_PRIME_LOWER_THAN_63BIT = 9223372036854775783;

template <class T> using reversed_priority_queue = priority_queue<T, vector<T>, greater<T> >;

template <typename Monoid>
struct segment_tree
{

	using underlying_type = typename  Monoid::underlying_type;

	segment_tree(ll a_n) : size_original(a_n)
	{
		vector<underlying_type> initial_value = vector<underlying_type>(a_n, Monoid::unit());
		segment_tree_impl(a_n, initial_value);
	}

	segment_tree(ll a_n, vector<underlying_type>& initial_value) : size_original(a_n)
	{
		segment_tree_impl(a_n, initial_value);
	}

	void update(int i, underlying_type z) { // 0-based
		assert(0 <= i && i < 2 * n - 1);
		a[i + n - 1] = z;
		for (i = (i + n) / 2; i > 0; i /= 2) { // 1-based
			a[i - 1] = Monoid::append(a[2 * i - 1], a[2 * i]);
		}
	}

	underlying_type query(ll l, ll r) { // 0-based, [l, r)
		underlying_type lacc = Monoid::unit(), racc = Monoid::unit();
		assert(l <= r && r <= n);
		l += n; r += n;
		for (; l < r; l /= 2, r /= 2) { // 1-based loop, 2x faster than recursion
			if (l % 2 == 1) lacc = Monoid::append(lacc, a[(l++) - 1]);
			if (r % 2 == 1) racc = Monoid::append(a[(--r) - 1], racc);
		}
		return Monoid::append(lacc, racc);
	}

	ll size() { return size_original; }

private:
	ll size_original;
	ll n;
	vector<underlying_type> a;
	void segment_tree_impl(ll a_n, vector<underlying_type>& initial_value)
	{
		assert(a_n == initial_value.size());
		n = 1; while (n < a_n) n *= 2;
		a.resize(2 * n - 1, Monoid::unit());
		rep(i, 0, initial_value.size()) {
			a[i + (n - 1)] = initial_value[i];
		}
		rrep(i, 0, n - 1) a[i] = Monoid::append(a[2 * i + 1], a[2 * i + 2]); // propagate initial values
	}
};


template <typename T>
struct min_indexed_t {
	typedef pair<T, ll> underlying_type;
	static underlying_type make_indexed(vector<T> v)
	{
		underlying_type w(v.size());
		rep(i, 0, v.size()) {
			w[i] = { v[i],i };
		}
		return w;
	}
	static underlying_type unit() { return make_pair(numeric_limits<T>::max(), -1); }
	static underlying_type append(underlying_type a, underlying_type b) { return min(a, b); }
};
template <typename T>
struct min_t {
	typedef T underlying_type;
	static underlying_type unit() { return numeric_limits<T>::max(); }
	static underlying_type append(underlying_type a, underlying_type b) { return min(a, b); }
};
struct linear_t {
	typedef pd underlying_type;
	static underlying_type unit() { return underlying_type{ 1.,0. }; }
	static underlying_type append(underlying_type a, underlying_type b) {
		return underlying_type{ a.first*b.first, b.first*a.second + b.second };
	}
};

class Combination {
	// this calculates combination (nCk).
	// Constructor runs in O(MAX).
	// get(n,k) returns nCk in O(1).

	ll MAX, MOD;
	vll fac;
	vll finv;
	vll inv;
public:
	Combination(ll MAX = 210000, ll MOD = 1000000007)
		:MOD(MOD), MAX(MAX), fac(vll(MAX)), finv(vll(MAX)), inv(vll(MAX)) {
		fac[0] = fac[1] = 1;
		finv[0] = finv[1] = 1;
		inv[1] = 1;
		rep(i, 2, MAX) {
			fac[i] = fac[i - 1] * i % MOD;
			inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
			finv[i] = finv[i - 1] * inv[i] % MOD;
		}
	}

	ll get(ll n, ll k) {
		if (n < k)return 0;
		if (n < 0 || k < 0)return 0;
		return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
	}
};


ll choose(int n, int r) { // O(r) for small n
	ll acc = 1;
	rep(i,0, r) 
		acc = acc * (n - i) / (i + 1);
	return acc;
}

int main() {

	ll N, P;
	cin >> N >> P;
	vll A(N);
	rep(i, 0, N) {
		cin >> A[i];
		A[i] = A[i] % 2;
	}
	sort(all(A));
	ll n0 = distance(A.begin(), upper_bound(all(A), 0));
	ll n1 = N - n0;
	ll res = 0;
	if (P == 0) {
		ll res0=1LL << n0;
		ll res1 = 0;
		for (ll i = 0; 2 * i <= n1; ++i) {
			res1 +=choose(n1, 2*i) ;
		}
		res = res0 * res1;
	}
	else {
		ll res0 = 1LL << n0;
		ll res1 = 0;
		for (ll i = 0; 2 * i+1 <= n1; ++i) {
			res1 += choose(n1,2*i+1) ;
		}
		res = res0 * res1 ;
	}
	cout << res;
	return 0;
}

Submission Info

Judge Result