Submission #1219754

#	Time	Username	Problem	Language	Result	Execution time	Memory
1219754		poat	Port Facility (JOI17_port_facility)	C++17	0 / 100	11 ms	23872 KiB

port_facility

// #pragma GCC optimize("Ofast")
// #pragma GCC target("popcnt")
 
#include <bits/stdc++.h>
using namespace std;
 
#define int long long
// #define double long double
#define mkp make_pair
 
#define txt freopen("shortcut.in", "r", stdin), freopen("shortcut.out", "w", stdout);
const int N = 1e6 + 10, K = 29, inf = 1e16, mod = 1e9 + 7;
const double eps = 1e-6;


struct seg
{
    vector<int> t;
    int n;

    bool fl = 0; // 1 = max, 0 = min

    seg(int n_, int f)
    {
        n = n_;
        fl = f;
        t.resize(n * 4, (fl ? 0 : 1e9));
    }

    int comb(int x, int y)
    {
        return (fl ? max(x, y) : min(x, y));
    }

    void upd(int x, int l, int r, int ind, int val)
    {
        if(l == r)
        {
            t[x] = val;
            return;
        }
        int m = (l + r) / 2;
        if(ind <= m)
            upd(x * 2, l, m, ind, val);
        else
            upd(x * 2 + 1, m + 1, r, ind, val);
        t[x] = comb(t[x * 2], t[x * 2 + 1]);
    }

    int get(int x, int l, int r, int tl, int tr)
    {
        if(tl > tr)
            return (fl ? 0 : 1e9);
        if(l == tl && r == tr)
            return t[x];
        int m = (l + r) / 2;
        return comb(get(x * 2, l, m, tl, min(m, tr)),
                get(x * 2 + 1, m + 1, r, max(tl, m + 1), tr));
    }
};


vector<int> gr[N];
int col[N];
bool f0 = 1;
void dfs(int x)
{
    for(auto i : gr[x])
    {
        if(!col[i])
        {
            col[i] = 3 - col[x];
            dfs(i);
        }
        else if(col[i] == col[x])
            f0 = 0;
    }
}


void solve()
{
    int n;
    cin >> n;


    vector<pair<int, int>> vec;

    int A[n + 5], B[n + 5];
    for(int i = 1; i <= n; i++)
    {
        cin >> A[i] >> B[i];
        vec.push_back({A[i], B[i]});
    }
    sort(vec.begin(), vec.end());
    
    for(int i = 1; i <= n; i++)
    {
        for(int j = i + 1; j <= n; j++)
        {
            if((A[i] > A[j] && A[i] < B[j] && B[i] > B[j]) || (A[j] > A[i] && A[j] < B[i] && B[j] > B[i]))
            {
                gr[i].push_back(j);
                gr[j].push_back(i);
            }
        }
    }

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

    if(!f0)
    {
        cout << "0\n";
        return;
    }
    
    seg mn(n * 2, 0);
    for(int i = 1; i <= n; i++)
        mn.upd(1, 1, n * 2, B[i], A[i]);
    
    int res = 0;

    for(auto i : vec)
    {
        int x = mn.get(1, 1, n * 2, i.first, i.second);
        if(x == i.first)
            res++;
        if(x == 0)
            assert(0);
    }

    int ans = 1;
    for(int it = res; it--;)
        ans = ans * 2 % mod;

    cout << ans << "\n";

    
    
}

signed main()
{   
    // txt;
    ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    int T = 1;
    for(; T--; solve());
}
/*
*/

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