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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
//#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//~ while (clock()<=69*CLOCKS_PER_SEC)

#define ll long long
#define ld long double
#define pi pair<int,int>
#define pd pair<ld,ld>
#define ft first
#define sd second
#define st first
#define nd second
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define FOR(i,a,b) for(int i=(a); i<=(b);i++)
#define F(i,a,b) FOR(i,(a),(b)-1)
#define REV(i,a,b) for(int i=(a); i>=(b);i--)
#define VI vector<int>
#define VPI vector<pi>
#define VPD vector<pd>
#define PI 3.14159265
#define all(x) (x).begin(), (x).end()
#define sz(a) (int)((a).size())
#define int long long

template<class TH> void _dbg(const char *sdbg, TH h){cerr<<sdbg<<"="<<h<<"\n";}
template<class TH, class... TA> void _dbg(const char *sdbg, TH h, TA... a) {
	while(*sdbg!=',')cerr<<*sdbg++;cerr<<"="<<h<<","; _dbg(sdbg+1, a...);
}
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const long long K = 1000;
const long long KK = K*K;
const long long MIL = KK*K;
const long long INF = MIL*MIL;
const long long MOD = 1e9 + 7;
const long long N = 1e5 + 10, M=10;

void solve() {
	int n;
	cin >> n;
	VI v(n + 1);

	FOR(i, 1, n) {
		cin >> v[i];
	}

	if (n <= 10000) {
		VI dp(n + 1);
		dp[0] = 1;

		FOR(i, 1, n) {
			int tmp = 0;
			REV(j, i, 1) {
				tmp += v[j];
				if ((tmp % MOD) % 2 == 0) {
					dp[i] += dp[j - 1];
				}
			}
			dp[i] %= MOD;
		}

		cout << dp[n]<< "\n";
	} else {
		int res = 0;
		int counter = 0;
		bool was_one = false;
		for (int i = 1; i < sz(v); i++) {
			if (v[i] % 2 == 1) {
				if (was_one) {
					was_one = false;
					counter++;
				} else {
					was_one = true;
				}
			} else {
				if (!was_one) {
					counter++;
				}
			}
		}

		if (counter == 0 || was_one) {
			cout << "0\n";
			return;
		} else {
			res = 1;
			F(i, 0, counter - 1) {
				res *= 2;
				res %= MOD;
			}
		}

		cout << res << "\n";
	}
}

int32_t main()
{
	//	freopen("input.txt", "r", stdin);
	//	freopen("output.txt", "w", stdout);

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cerr.tie(0);
	cout<<setprecision(9)<<fixed;
	cerr<<setprecision(6)<<fixed;
	int test = 1, f;
//	cin>>test;
	F(_test, 0, test){
		//cout<<"Case #"<<_test + 1<<": ";
		solve();
		//		if(_test == 1)
		//            return 0;
	}
}
/*
10
1 1 1 1 1 1 1 1 1 1
 */