Submission #990462

#	Time	Username	Problem	Language	Result	Execution time	Memory
990462		LOLOLO	Port Facility (JOI17_port_facility)	C++17	100 / 100	1218 ms	230132 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
 
#define           f     first
#define           s     second
#define           pb    push_back
#define           ep    emplace
#define           eb    emplace_back
#define           lb    lower_bound
#define           ub    upper_bound
#define       all(x)    x.begin(), x.end()
#define      rall(x)    x.rbegin(), x.rend()
#define   uniquev(v)    sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define     mem(f,x)    memset(f , x , sizeof(f))
#define        sz(x)    (ll)(x).size()
#define  __lcm(a, b)    (1ll * ((a) / __gcd((a), (b))) * (b))
#define          mxx    *max_element
#define          mnn    *min_element
#define    cntbit(x)    __builtin_popcountll(x)
#define       len(x)    (int)(x.length())
 
const int N = 1e6 + 10;
int p[N], sz[N], cnt, col[N], id[N * 2];
vector <int> ed[N];

int get(int x) {
    return p[x] ? get(p[x]) : x;
}

bool same(int a, int b) {
    return get(a) == get(b);
}

bool add_edge(int a, int b) {
    a = get(a), b = get(b);
    if (a == b)
        return 0;

    cnt--;
    if (sz[a] < sz[b]) {
        swap(a, b);
    }

    sz[a] += sz[b];
    p[b] = a;
    return 1;
}

bool insersect(vector <pair <int, int>> seg) {
    sort(all(seg));
    set <int> save;
    for (auto x : seg) {
        auto it = save.lower_bound(x.f);
        if (it != save.end() && *it < x.s)
            return 1;
 
        save.insert(x.s);
    }
 
    return 0;
}

void dfs(int u) {
    for (auto x : ed[u]) {
        if (col[x] == -1) {
            col[x] = 1 ^ col[u];
            dfs(x);
        }
    }
}

ll solve() {
    mem(col, -1);
    vector <pair <int, int>> seg;
    int n;
    cin >> n;

    for (int i = 1; i <= n; i++) {
        sz[i] = 1;
    }

    cnt = n;

    for (int i = 1; i <= n; i++) {
        int a, b;
        cin >> a >> b;
        seg.pb({a, b});
    }

    sort(all(seg));

    set <int> save;

    for (int i = 0; i < n; i++) {
        id[seg[i].f] = id[seg[i].s] = i + 1;
        auto it = save.lower_bound(seg[i].f);
        auto pr = save.lower_bound(seg[i].s);

        while (it != save.end() && *it < seg[i].s) {
            if (add_edge(i + 1, id[*it])) {
                ed[i + 1].pb(id[*it]);
                ed[id[*it]].pb(i + 1);
            }

            if (same(id[*it], id[*prev(pr)]))
                break;

            it = next(it);
        }

        save.insert(seg[i].s);
    }

    for (int i = 1; i <= n; i++) {
        if (col[i] == -1) {
            col[i] = 0;
            dfs(i);
        }
    }

    vector <pair <int, int>> A, B;
    for (int i = 1; i <= n; i++) {
        if (col[i] == 0) {
            A.pb(seg[i - 1]);
        } else {
            B.pb(seg[i - 1]);
        }
    }

    if (insersect(A) || insersect(B))
        return 0;

    ll ans = 1, mod = 1e9 + 7;

    for (int i = 1; i <= cnt; i++) {
        ans = (ans + ans) % mod;
    }

    return ans;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
 
    int t = 1;
    //cin >> t;
 
    while (t--) {
        cout << solve() << '\n';
    }
 
    return 0;
} 

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