Submission #4307823

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Source Code Expand

#include "bits/stdc++.h"
 
typedef long long ll;
#define int ll
#define fi first
#define se second
#define SORT(a) sort(a.begin(),a.end())
#define rep(i,n) for(int i = 0;i < (n) ; i++) 
#define REP(i,n) for(int i = 0;i < (n) ; i++) 
#define MP(a,b) make_pair(a,b)
#define pb(a) push_back(a)
#define INF LLONG_MAX/2
 
using namespace std;
int MOD = 1000000007;
int kai[100010] = {0};
signed main(){
    
    int n;
    cin >> n;
    kai[0] = kai[1] = 1;
    for(int i = 2;i <= n;i++){
        kai[i] = i*kai[i-1];
        kai[i] %= MOD;
    }
    set<pair<int,int>> s;
    rep(i,n){
        int a;
        cin >> a;
        s.insert(MP(a,0));
    }
    rep(i,n){
        int a;
        cin >> a;
        s.insert(MP(a,1));
    }
    int wa = 0;
    int cnt = 0;
    int ans = 1;
    for(auto x:s){
        if(x.se == 1)wa++;
        if(x.se == 0){
            wa--;
            cnt++;
        }
        if(wa == 0){
            ans *= kai[cnt];
            ans %= MOD;
            cnt = 0;
        }
    }
    cout << ans << endl;
    return 0;   
}
// g++ -std=c++14 code1.cpp
// rm -r -f test;oj dl https://ddcc2019-final.contest.atcoder.jp/tasks/ddcc2019_final_a
// rm -r -f test;oj dl http://cf16-exhibition-final-open.contest.atcoder.jp/tasks/cf16_exhibition_final_a

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