1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;

#define MAXN 300300

#define X 1000000007

struct item {
	long long suma;
	long long licznik;
	int parzyste;
};

void print_item(item e) {
	cout << "ITEM: " << e.suma << ", " << e.licznik << ", " << e.parzyste << endl;
}

int main()
{
	int n;
	vector<long long> v;
	cin >> n;
	//cout << "CZYTAMY DANE" << endl;
	for (int i = 0; i < n; i++) {
		int input;
		cin >> input;
		v.push_back(input);
	}
	
	vector<item> items0;
	vector<item> items1;
	
	vector<item> *prev = &items0;
	vector<item> *next = &items1;
	
	items0.push_back(item());
	items0.back().suma = v[0];
	items0.back().licznik = 1;
	if (v[0] % 2 == 0) items0.back().parzyste = 1; else items0.back().parzyste = 0;
	
	//cout << "========================= ITERATION 0 =============================" << endl;
	//for (vector<item>::iterator iter = prev->begin(); iter != prev->end(); iter++) {
	//		cout << iter->suma << ", " << iter->licznik << ", " << iter->parzyste << endl;
	//}
	
	for (int i = 1; i < n; ++i) {
		//cout << "========================= ITERATION " << i << " =============================" << endl;
		long long singleton_count = 0;
		for(vector<item>::iterator iter = prev->begin(); iter != prev->end(); iter++) {
			//cout << "ODWIEDZAMY ";
			//print_item(*iter);
			if (iter->parzyste == 1) {
				singleton_count += iter->licznik;
				next->push_back(item());
				next->back().suma = (v[i] + iter->suma) % X;
				next->back().licznik = iter->licznik;
				next->back().parzyste = (next->back().suma % 2) == 0;
				//cout << "    DOKŁADAMY ";
				//print_item(next->back());
			} else {
				next->push_back(item());
				next->back().suma = (v[i] + iter->suma) % X;
				next->back().licznik = iter->licznik;
				next->back().parzyste = (next->back().suma % 2) == 0;
				//cout << "    DOKŁADAMY  ";
				//print_item(next->back());
			}
		}
		if (singleton_count > 0) {
			//cout << "DOKŁADAMY SINGLETON ";
			next->push_back(item());
			next->back().suma = v[i];
			next->back().licznik = singleton_count % X;
			next->back().parzyste = (v[i] % 2) == 0;
			//print_item(next->back());
		}
		
		//for (vector<item>::iterator iter = next->begin(); iter != next->end(); iter++) {
		//	cout << iter->suma << ", " << iter->licznik << ", " << iter->parzyste << endl;
		//}
		
		prev->clear();
		vector<item> *tmp = prev;
		prev = next;
		next = tmp;
	}
	vector<item> *toCheck;
	if (!prev->empty()) toCheck = prev;
	else toCheck = next;
	
    //cout << "+++++++++++++ RESULT +++++++++++++++++++++" << endl;
	long long sum = 0;
	for (vector<item>::iterator iter = prev->begin(); iter != prev->end(); iter++) {
		if (iter->parzyste == 1) sum = (sum + iter->licznik) % X;
		//cout << iter->suma << ", " << iter->licznik << ", " << iter->parzyste << endl;
	}
	
	cout << sum << endl;
	
}