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
// Author: Kajetan Ramsza
#include "bits/stdc++.h"
using namespace std;
#pragma GCC target ("avx")

#define rep(i, a, b) for(int i = (a); i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

template<typename F, typename S> ostream& operator<<(ostream& os, const pair<F, S> &p) { return os<<"("<<p.first<<", "<<p.second<<")"; }
template<typename T> ostream &operator<<(ostream & os, const vector<T> &v) { os << "{"; typename vector< T > :: const_iterator it;
    for( it = v.begin(); it != v.end(); it++ ) { if( it != v.begin() ) os << ", "; os << *it; } return os << "}"; }

void dbg_out() { cerr<<'\n'; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr<<' '<<H; dbg_out(T...); }

#ifdef DEBUG
#define dbg(...) cerr<<"(" << #__VA_ARGS__ <<"):", dbg_out(__VA_ARGS__)
#else
#define dbg(...) 
#endif

const ll mod = 1e9 + 7;

ll modpow(ll b, ll e) {
	ll ans = 1;
	for (; e; b = b * b % mod, e /= 2)
		if (e & 1) ans = ans * b % mod;
	return ans;
}

const int limit = int(2e5) + 7;
ll fact[limit], inv_fact[limit];

void preprocess() { 
	fact[0] = 1;
	rep(i,1,limit) fact[i] = fact[i-1] * i % mod;
	inv_fact[limit-1] = modpow(fact[limit-1], mod-2);
	for(ll i=limit-2;i>=0;i--) inv_fact[i] = inv_fact[i+1] * (i+1) % mod;
}

ll choose(int n, int k) {
	return (fact[n] * inv_fact[k] % mod) * inv_fact[n-k] % mod;
}

int n, m;
vector<bool> lit;
vi color;

vector<vi> g;
vi stk;

bool is_biparte(int v) {
	stk.push_back(v);
	bool biparte = true;
	for(auto e : g[v]) {
		if(color[e] == -1) {
			color[e] = !color[v];
			biparte &= is_biparte(e);
		}
		if(color[e] == color[v]) biparte = false;
	}
	return biparte;
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	preprocess();
	cin>>n>>m;
	g.resize(n);
	lit.resize(n);
	rep(i,0,n) {
		char c; cin>>c;
		lit[i] = c == '1';
	}
	rep(i,0,m) {
		int a, b;
		cin>>a>>b;
		a--; b--;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	vector<ll> powers(n+1, 1);
	rep(i,0,n) powers[i+1] = powers[i] * 2LL % mod;

	color.assign(n, -1);
	ll res = 1;
	rep(i,0,n) {
		if(color[i] != -1) continue;
		stk.clear();
		color[i] = 0;
		bool biparte = is_biparte(i);
		if(!biparte) {
			res = res * powers[sz(stk)-1] % mod;
			continue;
		}
		int diff = 0, a = 0, b = 0;
		for(auto v : stk) {
			diff += (color[v] ? -1 : 1) * lit[v];
			if(color[v]) a++;
			else b++;
		}
		dbg(diff, a, b, stk);
		ll num = 0;
		rep(x,max(0,-diff),min(a,b-diff)+1) {
			num = (num + choose(a,x) * choose(b,x+diff)) % mod;
		}
		dbg(num);
		res = res * num % mod;
	}
	cout<<res<<'\n';
}