Submission #45593

#	Time	Username	Problem	Language	Result	Execution time	Memory
45593		golub	Port Facility (JOI17_port_facility)	C++14	0 / 100	3 ms	656 KiB

port_facility

#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;

using namespace std;

const int INF = 1e18;
const int MAXN = 30;
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 tree {
    struct node {
        unordered_set<int> a;
        node() {};
    };
    
    vector<node> d;
    int SZ = 1;
    
    tree(int n) {
        while (SZ < n) SZ *= 2;
        d.resize(4 * SZ);
    }
    
    void update(int x, int dx, int v, int l, int r) {
        if (x < l || x >= r) return;
        if (l + 1 >= r) {
            d[v].a.clear();
            d[v].a.insert(dx);
            return;
        }
        int c = (r + l) / 2;
        
        update(x, dx, v * 2 + 1, l, c);
        update(x, dx, v * 2 + 2, c, r);

        if (d[v * 2 + 1].a.size() > d[v * 2 + 2].a.size()) {
            d[v].a = d[v * 2 + 1].a;
            for (auto x: d[v * 2 + 2].a) {
                if (d[v].a.count(x)) {
                    d[v].a.erase(x);
                } else {
                    d[v].a.insert(x);
                }
            }
        } else {
            d[v].a = d[v * 2 + 2].a;
            for (auto x: d[v * 2 + 1].a) {
                if (d[v].a.count(x)) {
                    d[v].a.erase(x);
                } else {
                    d[v].a.insert(x);
                }
            }
        }
    }
    
    void update(int x, int dx) {
        update(x, dx, 0, 0, SZ);
    }
    
    unordered_set<int> query(int ql, int qr, int v, int l, int r) {
        if (qr <= l || r <= ql) return unordered_set<int>();
        if (ql <= l && r <= qr) return d[v].a;
        int c = (l + r) / 2;
        unordered_set<int> a = query(ql, qr, 2 * v + 1, l, c);
        unordered_set<int> b = query(ql, qr, 2 * v + 2, c, r);
        
        if (a.size() > b.size()) {
            for (auto x: b) {
                if (a.count(x)) {
                    a.erase(x);
                } else {
                    a.insert(x);
                }
            }
            return a;
        } else {
            for (auto x: a) {
                if (b.count(x)) {
                    b.erase(x);
                } else {
                    b.insert(x);
                }
            }
            return b;
        }
    }
    
    unordered_set<int> query(int ql, int qr) {
        return query(ql, qr, 0, 0, SZ);
    }
};

vector<pair<int, int>> a;

bool check(int in, int add) {
    if (in == -1) return 1;
    if (a[in].S < a[add].F) return 1;
    if (a[in].S > a[add].S) return 1;
    return 0;
}

void set_(int &in, int add) {
    if (in == -1) {
        in = add;
        return;
    }
    if (a[in].S < a[add].F) {
        in = add;
        return;
    }
    if (a[in].S > a[add].S) return;
}

vector<vector<int>> g;
vector<int> used;

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

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 == //
    int n;
    cin >> n;
    a.resize(n);
    vector<int> calc(2 * n);
    tree t(2 * n);
    for (int i = 0; i < n; i++) {
        cin >> a[i].F >> a[i].S;
        
        t.update(a[i].F - 1, i + 1);
        t.update(a[i].S - 1, i + 1);
        
        calc[a[i].F - 1] = i + 1;
        calc[a[i].S - 1] = -(i + 1);
    }
    int left = -1, right = -1;
    for (int i = 0; i < calc.size(); i++) {
        if (calc[i] > 0) {
            int add = calc[i] - 1;
            if (!check(left, add) && !check(right, add)) {
                cout << 0 << "\n";
                return 0;
            }
            if (check(left, add)) {
                set_(left, add);
                continue;
            }
            if (check(right, add)) {
                set_(right, add);
                continue;
            }
        }
    }
    g.resize(n);
    used.resize(n);
    for (int i = 0; i < n; i++) {
        auto ans = t.query(a[i].F - 1, a[i].S);
        for (auto x: ans) {
            g[i].pb(x - 1);
        }
    }
    int ans = 0;
    for (int i = 0; i < n; i++) {
        if (!used[i]) {
            dfs(i);
            ans++;
        }
    }
    cout << power(2, ans) << "\n";
    
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:190:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < calc.size(); i++) {
                     ~~^~~~~~~~~~~~~

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