Submission #656019

#	Time	Username	Problem	Language	Result	Execution time	Memory
656019		Kahou	Port Facility (JOI17_port_facility)	C++14	10 / 100	44 ms	32156 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], c[N], cnt;
set<pii> sl, sr;
bool bad;
vector<int> adj[N];

void dfs(int u) {
        for (int v:adj[u]) {
                if (!c[v]) {
                        c[v] = 3-c[u];
                        dfs(v);
                }
                else if (c[v] == c[u]) {
                        bad = 1;
                }
        }
}

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

                int prv = 1e9;
                for (auto it = sl.lower_bound({L[u], 0}); it != sl.end() && it->F < R[u]; it++) {
                        int v = it->S;
                        if (R[v] > prv) {
                                cout << 0 << endl;
                                return;
                        }
                        prv = R[v];
                        adj[u].push_back(v);
                        adj[v].push_back(u);
                }
        }

        for (int u = 1; u <= n; u++) {
                if (!c[u]) {
                        c[u] = 1;
                        cnt++;
                        dfs(u);
                }
        }

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

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

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