1228B.cpp

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

#define sz(x) (int)(x).size()
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pii;
typedef pair<ll,ll> pll;
typedef pair<ld,ld> pdd;

struct int_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

struct pair_hash {
    size_t operator()(pii x) const {
        return int_hash{}(x.first) ^ (int_hash{}(x.second) << 16);
    }
};

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<cd> vcd;
typedef vector<vector<int>> vvi;
typedef vector<vector<ll>> vvl;
typedef unordered_map<int, int> umpii;
typedef unordered_map<ll, ll> umpll;
typedef unordered_set<int> usi;
typedef unordered_set<ll> usll;
typedef unordered_set<pii, pair_hash> uspii;
typedef queue<int> qi;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int MOD = 1000000007;
const ll INF = 1e18;
const int inf = 1e9;
const int MX = 100001; //check the limits, dummy

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int h, w; cin >> h >> w;
    vi hs(h, 0), ws(w, 0);
    F0R(i, h) cin >> hs[i];
    F0R(i, w) cin >> ws[i];

    vvi g(h, vi(w, 0));
    F0R(i, h) {
        F0R(j, hs[i]) {
            if(i == ws[j]) {
                cout << 0 << endl;
                return 0;
            }
            g[i][j] = 1;
        }
    }

    F0R(i, w) {
        F0R(j, ws[i]) {
            if(i == hs[j]) {
                cout << 0 << endl;
                return 0;
            }
            g[j][i] = 1;
        }
    }

    int p = 0;
    F0R(i, h) {
        FOR(j, hs[i] + 1, w) {
            if(g[i][j] != 1 && i > ws[j]) {
                p++;
            }
        }
    }

    int ans = 1;
    while(p--) {
        ans = (ans * 2) % MOD;
    }
    cout << ans << endl;
}