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<iostream>
#include<math.h>
#include<vector>

using namespace std;

long long modulo = pow(10,9)+7;

long long result = 1;
int n,m;
vector<int> graf[200100];

bool visited[200100];
int c[200100];

int group_array[200100];

long long group_counter[2];
long long black_counter[2];

bool is_odd;
int component_n;

long long silnia[200100];

void dfs(int v, int group) {
    component_n++;
    visited[v] = true;
    group_array[v] = group;
    group_counter[group] ++;
    black_counter[group] += c[v];
    
    for(int w : graf[v]) {
        if(visited[w]) {
            if(group_array[w] == group) is_odd = true;
            continue;
        }
        
        dfs(w, 1-group);
    }
}

long long odwrotnosc(long long x) {
    long long res = 1;
    int y = modulo-2;
    
    while (y > 0) {
        if (y % 2 == 1)
            res = (res * x)%modulo;
 
        y = y >> 1;
        x = (x * x)%modulo;
    }
    
    return res;
}

long long power_of_two() {
    long long wynik = 1;
    for(int i=0;i<component_n-1;i++)
        wynik = (wynik*2)%modulo;
        
    return wynik;
}

long long binomial_calculator(int n, int k){
    long long wynik = silnia[n];
    wynik = (wynik * odwrotnosc(silnia[k]))%modulo;
    wynik = (wynik * odwrotnosc(silnia[n-k]))%modulo;
    
    return wynik;
}

long long count_binomial() {
    if(black_counter[0] < black_counter[1]) {
        swap(group_counter[0], group_counter[1]);
        swap(black_counter[0], black_counter[1]);
    }
    
    long long wynik = 0;
    int roznica = black_counter[0]-black_counter[1];
    
    for(int i=0;i<=group_counter[1];i++) {
        if(i + roznica > group_counter[0]) break;
        wynik += (binomial_calculator(group_counter[0], i+roznica)*binomial_calculator(group_counter[1], i))%modulo;
        wynik %= modulo;    
    }
    
    return wynik;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    
    cin>>n>>m;
    
    silnia[0] = 1;
    for(long long i=1;i<=n;i++)
        silnia[i] = (i*silnia[i-1])%modulo;
    
    for(int i=1;i<=n;i++)cin>>c[i];
    for(int i=0;i<m;i++) {
        int a,b;
        cin>>a>>b;
        graf[a].push_back(b);
        graf[b].push_back(a);
    }

    for(int i=1;i<=n;i++) {
        if(visited[i]) continue;
        
        for(int j=0;j<2;j++) {
            group_counter[j] = 0;
            black_counter[j] = 0;
        }
        
        is_odd = false;
        component_n = 0;

        dfs(i, 0);

        if(is_odd) //nieparzysty cykl
            result *= power_of_two();
        else
            result *= count_binomial();
            
        result %= modulo;
    }
    
    cout<<result<<endl;

    return 0;
}