Source Code
// Those who cannot remember the past are
// condemned to repeat it (use DP -_-)
// - George Santayana

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

using namespace std;
using namespace __gnu_pbds;

#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define ll long long
#define ull unsigned long long
#define MOD 1000000007
#define PI 3.14159265
#define ceil(a, b) ((a / b) + (a % b ? 1 : 0))
#define imin INT_MIN
#define imax INT_MAX
#define inf 2000000000
#define nl '\n'
#define ppcnt __builtin_popcount
#define ppcntll __builtin_popcountll
#define clz __builtin_clz
#define clzll __builtin_clzll
#define ctz __builtin_ctz
#define ctzll __builtin_ctzll
#define modulo(a, b, mod) ((((a) % mod) * ((b) % mod)) % mod)
#define cnte(v, x) count(all(v), (x))
#define mine(v) min_element(all(v))
#define maxe(v) max_element(all(v))
#define debug(x) cout << "x: " << x << nl;
#define debug2(x, y) cout << "x: " << x << " y: " << y << nl;
#define ordered_set tree<pair<int, int>, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update>
#define ordered_map tree<int, int, less<>, rb_tree_tag, tree_order_statistics_node_update>

//vector<int> dx = {0, 0, 1, -1, 1, 1, -1, -1}, dy = {1, -1, 0, 0, 1, -1, 1, -1};
//vector<int> dx = {0, 0, 1, -1}, dy = {1, -1, 0, 0};

template<typename T = int> istream& operator>>(istream& in, vector<pair<int, int>>& v){
    for (auto& [x, y] : v) in >> x >> y;
    return in;
}

template<typename T = int> istream& operator>>(istream& in, vector<T>& v){
    for (T& i : v) in >> i;
    return in;
}

template<typename T = int> ostream& operator<<(ostream& out, const vector<T>& v){
    for (const T& x : v)
        out << x << ' ';
    return out;
}

template<typename T = pair<int, int>> ostream& operator << (ostream& out, const vector<pair<int, int>>& v){
    for(auto& [x, y] : v){
        out << x << ' ' << y << nl;
    }
    return out;
}

void Start_Crushing() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}

struct MOD_Inverse {

    ll n;
    vector<ll> fact, inv;

    ll fast_power(ll b, ll e){
        ll power = 1;
        while(e){
            if(e & 1) power = modulo(power, b, MOD);
            e >>= 1, b = modulo(b, b, MOD);
        }
        return power % MOD;
    }

    ll Inverse(ll x){
        return fast_power(x, MOD - 2) % MOD;
    }

    MOD_Inverse(ll n){
        this -> n = n;
        fact.assign(n + 10, 1), inv.resize(n + 10, 1);
        for(ll i = 1; i <= n; i++){
            fact[i] = modulo(fact[i - 1], i, MOD);
            inv[i] = Inverse(fact[i]);
        }
    }

};


void solve(){
    int n; cin >> n;
    vector<int> a(n), b(n); cin >> a >> b;

    ll sum = 0;
    vector<int> s;
    for(int i = 0; i < n; i++){
        if(a[i] > b[i] or (b[i] - a[i]) % (i + 1))
            return void(cout << 0);
        s.emplace_back((b[i] - a[i]) / (i + 1));
        sum += (b[i] - a[i]) / (i + 1);
    }
    MOD_Inverse p(2e6 + 5);

    ll total = 1;
    for(int i = 2; i <= sum; i++){
        total = modulo(total, i, MOD);
    }

    for(auto& i : s){
        total = modulo(total, p.inv[i], MOD);
    }
    cout << total;
}

int main(){
    Start_Crushing();

    int t = 1;
//    /*Multiple test cases?*/ cin >> t;
    while (t--) {
        solve();
        if(!t) break;
        cout << nl;
    }

//    for(int tc = 1; tc <= t; tc++){
//        cout << "Case #" << tc << ": ";
//        solve();
//        if(tc != t)
//            cout << nl;
//    }

    return 0;
}
Copy
N-dimensions El_Gemmy
GNU G++17
504 ms
34.1 MB
Accepted