Submission #655963

#	Time	Username	Problem	Language	Result	Execution time	Memory
655963		Kahou	Port Facility (JOI17_port_facility)	C++14	0 / 100	1 ms	340 KiB

port_facility

#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define endl '\n'
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int mod = 1e9 + 7;
int mul(int a, int b) {
        return 1ll*a*b%mod;
}
int pw(int a, int b) {
        int out = 1;
        while (b) {
                if (b&1) out = mul(out, a);
                a = mul(a,a);
                b>>=1;
        }
        return out; 
}


const int N = 1e6 + 50;
int n, L[N], R[N], par[N], sz[N], cnt;
set<pii> sl, sr;

int getroot(int u) {
        if (u == par[u]) return u;
        return par[u] = getroot(par[u]);
}
void uniset(int u, int v) {
        u = getroot(u), v = getroot(v);
        if (u == v) return;
        if (sz[u] < sz[v]) swap(u, v);
        par[v] = u;
        sz[u] += sz[v];
        cnt--;
}

void solve() {
        cin >> n;
        cnt = n;
        for (int i = 1; i <= n; i++) {
                cin >> L[i] >> R[i];
                sl.insert({L[i], i});
                sr.insert({R[i], i});
                par[i] = i;
                sz[i] = 1;
        }
        bool flg = 1;
        while (sr.size()) {
                int u = sr.begin()->S;
                sr.erase(sr.begin());
                sl.erase({L[u], u});

                for (auto it = sl.lower_bound({L[u], 0}); it != sl.end() && it->F < R[u]; it++) {
                        int v = it->S;
                        if (getroot(u) == getroot(v)) {
                                flg = 0;
                                break;
                        }
                        uniset(u, v);
                }
                if (!flg) break;
        }
        if (!flg) return cout << 0 << endl, void();

        cout << pw(2, cnt) << endl;
}

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

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