Submission #1202882

#	Time	Username	Problem	Language	Result	Execution time	Memory
1202882		JooDdae	Port Facility (JOI17_port_facility)	C++20	0 / 100	33 ms	63040 KiB

port_facility

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

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

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][0].size()+s[x][1].size() > s[y][0].size()+s[y][1].size()) swap(x, y);

    int k = d[x] == d[y];
    for(int i=0;i<2;i++) {
        while(!s[x][i].empty()) {
            auto [c, u] = s[x][i].top(); s[x][i].pop();
            s[y][i^k].push({c, u}), d[u] = i^k;
        }
    }
    p[x] = y;

    return 1;
}

void add(int u, int i) {
    for(int j=0;j<2;j++) {
        while(!s[u][j].empty() && s[u][j].top()[0] <= i) s[u][j].pop();
        if(!s[u][j].empty()) pq.push(s[u][j].top());
    }
}

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][0].push({b[i], 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 || c < a[u]) continue;
            P = c;

            if(find(x) == find(u) && d[x] != d[u]) return cout << 0, 0;
            merge(x, u);
        }

        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