Submission #963672

#	Time	Username	Problem	Language	Result	Execution time	Memory
963672		Cookie	Port Facility (JOI17_port_facility)	C++14	0 / 100	2 ms	2652 KiB

port_facility

#include<bits/stdc++.h>
#include<fstream>
using namespace std;
#define sz(a) (int)a.size()
#define ALL(v) v.begin(), v.end()
#define ALLR(v) v.rbegin(), v.rend()
#define ll long long
#define pb push_back
#define forr(i, a, b) for(int i = a; i < b; i++)
#define dorr(i, a, b) for(int i = a; i >= b; i--)
#define ld long double
#define vt vector
#include<fstream>
#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>
#define mpp make_pair
const ld PI = 3.14159265359, prec = 1e-9;;
//using u128 = __uint128_t;
//const int x[4] = {1, 0, -1, 0};
//const int y[4] = {0, -1, 0, 1};
const ll mod = 1e9 + 7, pr = 31;
const int mxn = 1e5 + 5, mxq = 1e5 + 5, sq = 500, mxv = 5e4 + 1;
//const int base = (1 <<18);
const ll inf = 1e9 + 5, neg = -69420, inf2 = 1e14;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
// have fun!
//JOIIIIIIIIIIIIIII
int n;
int c[mxn + 1];
pii p[mxn + 1];
vt<int>adj[mxn + 1];
bool bad = 0, used[mxn + 1];
void dfs(int s){
    for(auto i: adj[s]){
        if(c[i] == -1){
            c[i] = c[s] ^ 1; dfs(i);
        }else if(c[i] != (c[s] ^ 1))bad = 1;
    }
}
void solve(){
    cin >> n;
    for(int i = 1; i <= n; i++)cin >> p[i].fi >> p[i].se;
    sort(p + 1, p + n + 1);
    set<int>s;
    for(int i = 1; i <= n; i++){
        auto it = s.lower_bound(p[i].fi);
        if(it == s.end() || *it > p[i].se){
            used[i] = 1; s.insert(p[i].se);
        }
    }
    s.clear();
    for(int i = 1; i <= n; i++){
        if(!used[i]){
            auto it = s.lower_bound(p[i].fi);
            if(it == s.end() || *it > p[i].se){
                s.insert(p[i].se);
            }else{
                cout << 0;
                return;
            }
        }
    }
    for(int i = 1; i <= n; i++){
        for(int j = i + 1; j <= n; j++){
            if(p[j].fi < p[i].se && p[i].se < p[j].se){
                adj[i].pb(j); adj[j].pb(i);
            }
        }
    }
    ll ans = 1;
    for(int i = 1; i <= n; i++)c[i] = -1;
    for(int i = 1; i <= n; i++){
        if(c[i] == -1){
            c[i] = 1; dfs(i);
            ans = (ans * 2) % mod;
        }
    }
    if(bad){
        cout << 0; return;
    }
    cout << ans;
}
signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    //freopen("DATA.inp", "r", stdin);
    //freopen("DATA.out", "w", stdout);
    int tt; tt = 1;
    while(tt--){
        solve();
 
    }
    return(0);
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22