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
132
133
134
135
#include <bits/stdc++.h>
using namespace std;

constexpr int P = 1000000007;

int inv(int a)
{
	int x = 1, y = 0, q = P;
    int pos = 0;
    while (a > 0) {
        int r = q % a;
        q = q/a;
        int h = q*x + y;
        y = x;
        x = h;
        q = a;
        a = r;
        pos = !pos;
    }
    return pos ? y : (P - y);
}

int n;

vector<int> color;
vector<vector<int>> graph;
vector<int> visited;
vector<int> component;

void AddEdge(int a, int b)
{
	graph[a].push_back(b);
}

void Read()
{
	int m;
	scanf("%d%d", &n, &m);
	color.resize(n);
	graph.resize(n);
	for (int i = 0; i < n; i++)
		scanf("%d", &color[i]);
	for (int i = 0; i < m; i++)
	{
		int a, b;
		scanf("%d%d", &a, &b);
		a--; b--;
		AddEdge(a, b);
		AddEdge(b, a);
	}
}

bool DFS(int a, int depth = 1)
{
	component.push_back(a);
	visited[a] = depth;
	bool is_bipartite = true;
	for (int b : graph[a])
		if (visited[b])
			is_bipartite &= depth != visited[b];
		else
			is_bipartite &= DFS(b, depth ^ 3);
	return is_bipartite;
}

int Biparitie()
{
	int count[2][2] = {{0, 0}, {0, 0}};
	for (int a : component)
		count[visited[a] - 1][color[a]]++;
	int m[2];
	for (int i = 0; i < 2; i++)
		m[i] = count[i][0] + count[i][1];
	int k[2];
	{
		int min_k = min(count[0][0], count[1][0]);
		for (int i = 0; i < 2; i++)
			k[i] = count[i][0] - min_k;
	}
	int64_t binom = 1;
	for (int i = 0; i < 2; i++)
	{
		for (int j = 1; j <= k[i]; j++)
		{
			binom = (binom * (m[i] - j + 1)) % P;
			binom = (binom * inv(j)) % P;
		}
	}
	int res = 0;
	for (; k[0] <= m[0] && k[1] <= m[1]; k[0]++, k[1]++)
	{
		res = (res + binom) % P;
		for (int i = 0; i < 2; i++)
		{
			binom = (binom * (m[i] - k[i])) % P;
			binom = (binom * inv(k[i] + 1)) % P;
		}
	}
	return res;
}

int Connected()
{
	int res = 1;
	for (int i = 0; i < (int) component.size() - 1; i++)
		res = (res * 2) % P;
	return res;
}

int64_t SolveComponent(int r)
{
	component.clear();
	bool is_bipartite = DFS(r);
	if (is_bipartite)
		return Biparitie();
	else
		return Connected();
}

int Solve()
{
	int total = 1;
	visited.resize(n, 0);
	for (int i = 0; i < n; i++)
		if (!visited[i])
			total = (SolveComponent(i) * total) % P;
	return total;
}

int main()
{
	Read();
	printf("%d\n", Solve());
	return 0;
}