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
129
130
131
#include<bits/stdc++.h>
using namespace std;
using LL=long long;
#define FOR(i,l,r)for(int i=(l);i<=(r);++i)
#define REP(i,n)FOR(i,0,(n)-1)
#define ssize(x)int(x.size())
#ifdef DEBUG
auto operator<<(auto&o,auto x)->decltype(x.end(),o);
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto&operator<<(auto&o,tuple<auto,auto,auto>t){return o<<"("<<get<0>(t)<<", "<<get<1>(t)<<", "<<get<2>(t)<<")";}
auto&operator<<(auto&o,tuple<auto,auto,auto,auto>t){return o<<"("<<get<0>(t)<<", "<<get<1>(t)<<", "<<get<2>(t)<<", "<<get<3>(t)<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

constexpr int mod = int(1e9) + 7;
int add(int a, int b) {
	a += b;
	return a >= mod ? a - mod : a;
}
int sub(int a, int b) {
	return add(a, mod - b);
}
int mul(int a, int b) {
	return int(a * LL(b) % mod);
}
int powi(int a, int b) {
	for(int ret = 1;; b /= 2) {
		if(b == 0)
			return ret;
		if(b & 1)
			ret = mul(ret, a);
		a = mul(a, a);
	}
}
int inv(int x) {
	return powi(x, mod - 2);
}
struct BinomCoeff {
	vector<int> fac, rev;
	BinomCoeff(int n) {
		fac = rev = vector(n + 1, 1);
		FOR(i, 1, n) fac[i] = mul(fac[i - 1], i);
		rev[n] = inv(fac[n]);
		for(int i = n; i > 0; --i)
			rev[i - 1] = mul(rev[i], i);
	}
	int operator()(int n, int k) {
		return mul(fac[n], mul(rev[n - k], rev[k]));
	}
};

int main() {
	cin.tie(0)->sync_with_stdio(0);

	int n, m;
	cin >> n >> m;
	vector<int> in(n);
	REP(i, n)
		cin >> in[i];
	vector<vector<int>> graph(n);
	REP(i, m) {
		int a, b;
		cin >> a >> b;
		--a, --b;
		graph[a].emplace_back(b);
		graph[b].emplace_back(a);
	}
	debug(n, m, in, graph);

	BinomCoeff bc(n);
	int ans = 1;
	vector<int> color(n, -1);
	vector<bool> visited(n);
	REP(i, n) {
		if (visited[i])
			continue;
		vector cnt(2, 0), cnt_ones(2, 0);
		bool odd_cycle = false;
		function<void(int, int)> dfs = [&](int v, int c) {
			visited[v] = true;
			color[v] = c;
			++cnt[c];
			cnt_ones[c] += in[v];
			for (auto x : graph[v]) {
				if (visited[x]) {
					if (color[x] == c)
						odd_cycle = true;
				}
				else {
					dfs(x, c ^ 1);
				}
			}
		};
		dfs(i, 0);
		debug(i, odd_cycle, cnt, cnt_ones);
		if (odd_cycle) {
			ans = mul(ans, powi(2, cnt[0] + cnt[1] - 1));
		}
		else {
			const int size_left = cnt[0];
			const int size_right = cnt[1];
			int one_left = cnt_ones[0];
			int one_right = cnt_ones[1];
			int zero_left = cnt[0] - cnt_ones[0];
			int zero_right = cnt[1] - cnt_ones[1];
			{
				int diff = min(one_left, one_right);
				one_left -= diff;
				one_right -= diff;
				zero_left += diff;
				zero_right += diff;
			}
			int sum = 0;
			while (true) {
				sum = add(sum, mul(bc(size_left, one_left), bc(size_right, one_right)));
				if (not zero_left or not zero_right) {
					break;
				}
				++one_left;
				++one_right;
				--zero_left;
				--zero_right;
			}
			ans = mul(ans, sum);
		}
	}
	cout << ans << '\n';
}