Submission #2625941

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vl;

ll N;
ll ans = 1;
ll mod = (ll)1e9+7;

void solve() {
    cin >> N;
    vector<pii> obj;
    rep(i,N) {
        int a;
        cin >> a;
        obj.push_back(pii(a, 0));
    }
    rep(i,N) {
        int a;
        cin >> a;
        obj.push_back(pii(a, 1));
    }
    sort(obj.begin(), obj.end());
    multiset<int> st1, st2;
    rep(i,2*N) {
        if (obj[i].second == 0) {
            if (st2.empty()) {
                st1.insert(obj[i].first);
            } else {
                ans *= st2.size();
                ans %= mod;
                st2.erase(st2.begin());
            }        
        } else {
            if (st1.empty()) {
                st2.insert(obj[i].first);
            } else {
                ans *= st1.size();
                ans %= mod;
                st1.erase(st1.begin());
            }     
        }
    }
    cout << ans << endl;
}

int main() {
    cin.tie(0);
   	ios::sync_with_stdio(false);
    solve();
    return 0;
}

Submission Info

Judge Result