Submission #1202840

#	Time	Username	Problem	Language	Result	Execution time	Memory
1202840		JooDdae	Port Facility (JOI17_port_facility)	C++20	0 / 100	13 ms	31552 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int n, a[1001001], b[1001001], p[1001001], c[2002002];
priority_queue<array<int, 2>, vector<array<int, 2>>, greater<>> pq;
priority_queue<int, vector<int>, greater<>> s[1001001];

int find(int x) { return x == p[x] ? x : p[x] = find(p[x]); }
int merge(int x, int y) {
    if((x = find(x)) == (y = find(y))) return 0;
    if(s[x].size() > s[y].size()) swap(x, y);
    while(!s[x].empty()) s[y].push(s[x].top()), s[x].pop();
    p[x] = y;
    return 1;
}

void add(int u, int i) {
    while(!s[u].empty() && s[u].top() <= i) s[u].pop();
    while(!pq.empty() && pq.top()[0] <= i) pq.pop();

    if(s[u].empty()) return;
    int x = s[u].top(); s[u].pop();
    pq.push({x, u});
    if(!s[u].empty()) {
        pq.push({s[u].top(), u});
    }
    s[u].push(x);
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> n;
    for(int i=1;i<=n;i++) cin >> a[i] >> b[i];
    for(int i=1;i<=n;i++) c[a[i]] = c[b[i]] = p[i] = i, s[i].push(b[i]);

    for(int i=1;i<=n+n;i++) {
        int u = c[i];

        if(i == b[u]) {
            add(find(u), i);
            continue;
        }
        
        int P = 0;
        while(!pq.empty() && pq.top()[0] < b[u]) {
            auto [c, x] = pq.top(); pq.pop();
            if(c == P) continue;
            P = c;
            if(!merge(x, u)) return cout << 0, 0;
        }
        add(find(u), i);
    }

    int ans = 1;
    for(int i=1;i<=n;i++) if(i == find(i)) ans = ans * 2 % 1000000007;
    cout << ans;
}

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