Submission #45915

#	Time	Username	Problem	Language	Result	Execution time	Memory
45915		golub	Port Facility (JOI17_port_facility)	C++11	100 / 100	5194 ms	333044 KiB

port_facility

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,sse4")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("unroll-all-loops")

#include<cstring>
#include<iostream>

using namespace std;

char buf[(long long)5e8];
size_t p_ = 0;

void *operator new(size_t n_) {
    p_ += n_;
    return buf + p_ - n_;
}
void operator delete(void*) {};

#include <bits/stdc++.h>

//#define TASK "lca"

#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define F first
#define S second
#define pb push_back
//#define int long long
#define pii pair<int, int>

//typedef long long ll;
//typedef long double ld;



const int INF = 1e9 + 100;
const int MAXN = 1e6 * 2;
const int MOD = 1e9 + 7;
const double EPS = 1e-12;

//ll power(ll x, ll n, ll mod = 1e9 + 7) {
//    if (n == 0) return 1ll;
//    if (n & 1ll) return power(x, n - 1ll, mod) * x % mod;
//    ll tmp = power(x, n >> 1ll, mod);
//    return (tmp * tmp) % mod;
//}
//
//ll gcd(ll a, ll b) {
//    if (b == 0) return a;
//    return gcd (b, a % b);
//}
//
//ll lcm(ll a, ll b) {
//    return a / gcd(a, b) * b;
//}

struct seg_max {
    vector<int> d;
    int SZ = 1;
    
    seg_max(int n = 0) {
        while(SZ < n) SZ *= 2;
        d.resize(SZ * 2, -INF);
    }
    
    void update(int x, int dx, int v, int l, int r) {
        if (x < l || x >= r) return;
        if (l + 1 >= r) {
            d[v] = dx;
            return;
        }
        int c = (r + l) / 2;
        update(x, dx, v * 2 + 1, l, c);
        update(x, dx, v * 2 + 2, c, r);
        d[v] = max(d[v * 2 + 1], d[v * 2 + 2]);
    }
    
    void update(int x, int dx) {
        update(x, dx, 0, 0, SZ);
    }
    
    int query(int ql, int qr, int v, int l, int r) {
        if (qr <= l || r <= ql) return -INF;
        if (ql <= l && r <= qr) return d[v];
        int c = (l + r) / 2;
        return max(query(ql, qr, 2 * v + 1, l, c), query(ql, qr, 2 * v + 2, c, r));
    }
    
    int query(int ql, int qr) {
        return query(ql, qr, 0, 0, SZ);
    }
};

struct seg_min {
    vector<int> d;
    int SZ = 1;
    
    seg_min(int n = 0) {
        while(SZ < n) SZ *= 2;
        d.resize(SZ * 2, INF);
    }
    
    void update(int x, int dx, int v, int l, int r) {
        if (x < l || x >= r) return;
        if (l + 1 >= r) {
            d[v] = dx;
            return;
        }
        int c = (r + l) / 2;
        update(x, dx, v * 2 + 1, l, c);
        update(x, dx, v * 2 + 2, c, r);
        d[v] = min(d[v * 2 + 1], d[v * 2 + 2]);
    }
    
    void update(int x, int dx) {
        update(x, dx, 0, 0, SZ);
    }
    
    int query(int ql, int qr, int v, int l, int r) {
        if (qr <= l || r <= ql) return INF;
        if (ql <= l && r <= qr) return d[v];
        int c = (l + r) / 2;
        return min(query(ql, qr, 2 * v + 1, l, c), query(ql, qr, 2 * v + 2, c, r));
    }
    
    int query(int ql, int qr) {
        return query(ql, qr, 0, 0, SZ);
    }
};

vector<pair<int, int>> a;
vector<vector<int>> g;
vector<int> used;
unordered_map<int, int> num1, num2;
seg_max seg_ma(MAXN);
seg_min seg_mi(MAXN);

void solve(int i, int color = 1) {
    seg_ma.update(a[i].F, -INF);
    seg_mi.update(a[i].S, INF);
    used[i] = color;
    
    vector<int> next;
    int l = a[i].F;
    int r = a[i].S;
    int ans = INF;
    while (ans > r) {
        ans = seg_ma.query(l, r + 1);
        if (ans <= r) break;
        int p = num1[ans];
        if (used[p] && used[p] == color) {
            cout << 0 << '\n';
            exit(0);
        }
        used[p] = color % 2 + 1;
        next.pb(p);
//        if (!used[p]) {
//            g[i].pb(p);
//            g[p].pb(i);
//
//        }
        seg_ma.update(a[p].F, -INF);
    }
    ans = -INF;
    while (ans < l) {
        ans = seg_mi.query(l, r + 1);
        if (ans >= l) break;
        int p = num2[ans];
        
        if (used[p] && used[p] == color) {
            cout << 0 << '\n';
            exit(0);
        }
        used[p] = color % 2 + 1;
        next.pb(p);
//        if (!used[p]) {
//            g[i].pb(p);
//            g[p].pb(i);
//
//        }
        seg_mi.update(a[p].S, INF);
    }
    for (auto x: next) {
        solve(x, color % 2 + 1);
    }
}

void dfs(int v, int color = 1) {
    used[v] = color;
    for (auto u: g[v]) {
        if (u != v && used[u] && used[u] == color) {
            cout << 0 << "\n";
            exit(0);
        }
        if (!used[u]) dfs(u, color % 2 + 1);
    }
}

int n;
int ans = 1ll;

signed main() {
#ifndef LOCAL
#ifdef TASK
    freopen(TASK".in", "r", stdin);
    freopen(TASK".out", "w", stdout);
#endif
#endif
#ifdef LOCAL
    //freopen("/Users/alekseygolub/Desktop/с++/ABS/ABS/input.txt", "r", stdin);
#endif
    iostream::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    srand(924653523);
    // == SOLUTION == //
    scanf("%d", &n);
    
    a.resize(n);
    used.resize(n);
    g.resize(n);
    
    for (int i = 0; i < n; i++) {
        pair<int, int> x;
        scanf("%d%d", &x.F, &x.S);
        x.F--; x.S--;
        a[i] = x;
        num1[x.S] = i;
        num2[x.F] = i;
        seg_ma.update(x.F, x.S);
        seg_mi.update(x.S, x.F);
    }
    for (int i = 0; i < n; i++) {
        if (!used[i]) {
            solve(i);
            ans = ans << 1ll;
            ans %= MOD;
        }
    }
//    fill(all(used), 0);
//    for (int i = 0; i < n; i++) {
//        if (!used[i]) {
//            dfs(i);
//        }
//    }
    cout << ans << '\n';
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:218:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
port_facility.cpp:226:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &x.F, &x.S);
         ~~~~~^~~~~~~~~~~~~~~~~~~~

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