Submission #670861

#	Time	Username	Problem	Language	Result	Execution time	Memory
670861		stevancv	Port Facility (JOI17_port_facility)	C++14	0 / 100	1 ms	340 KiB

port_facility

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 1e6 + 2;
const int mod = 1e9 + 7;
struct PST {
    int st[21 * N], lc[21 * N], rc[21 * N], root[N], tsz;
    void Add(int &c, int pc, int l, int r, int x) {
        c = ++tsz; st[c] = st[pc] + 1; lc[c] = lc[pc]; rc[c] = rc[pc];
        if (l == r) return;
        int mid = l + r >> 1;
        if (x <= mid) Add(lc[c], lc[pc], l, mid, x);
        else Add(rc[c], rc[pc], mid + 1, r, x);
    }
    int Get(int c, int l, int r, int ql, int qr) {
        if (r < ql || qr < l || c == 0) return 0;
        if (ql <= l && r <= qr) return st[c];
        int mid = l + r >> 1;
        return Get(lc[c], l, mid, ql, qr) + Get(rc[c], mid + 1, r, ql, qr);
    }
}pst[2];
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n; cin >> n;
    vector<array<int, 2>> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i][0] >> a[i][1];
    }
    sort(a.begin(), a.end(), [&] (array<int, 2> i, array<int, 2> j) {
        return i[1] < j[1];
    });
    vector<int> b(n);
    iota(b.begin(), b.end(), 0);
    for (int i = 0; i < n; i++) {
        int l = 0, r = i - 1;
        while (l <= r) {
            int mid = l + r >> 1;
            if (a[i][0] < a[mid][1]) {
                r = mid - 1;
                b[i] = mid;
            }
            else l = mid + 1;
        }
    }
    int ans = 1;
    for (int i = 0; i < n; i++) {
        int x = 0, y = 0;
        if (i > 0) {
            pst[0].root[i] = pst[0].root[i - 1];
            pst[1].root[i] = pst[1].root[i - 1];
            x += pst[0].Get(pst[0].root[i - 1], 1, 2 * n, 1, a[i][0]);
            y += pst[1].Get(pst[1].root[i - 1], 1, 2 * n, 1, a[i][0]);
        }
        if (b[i] > 0) {
            x -= pst[0].Get(pst[0].root[b[i] - 1], 1, 2 * n, 1, a[i][0]);
            y -= pst[1].Get(pst[1].root[b[i] - 1], 1, 2 * n, 1, a[i][0]);
        }
        if (x == 0 && y == 0) {
            ans *= 2;
            if (ans >= mod) ans -= mod;
            pst[0].Add(pst[0].root[i], pst[0].root[i - 1], 1, 2 * n, a[i][0]);
        }
        else if (x > 0 && y > 0) {
            cout << 0 << en;
            return 0;
        }
        else if (x > 0) pst[1].Add(pst[1].root[i], pst[1].root[i - 1], 1, 2 * n, a[i][0]);
        else pst[0].Add(pst[0].root[i], pst[0].root[i - 1], 1, 2 * n, a[i][0]);
    }
    cout << ans << en;
    return 0;
}

Compilation message (stderr)

port_facility.cpp: In member function 'void PST::Add(int&, int, int, int, int)':
port_facility.cpp:16:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   16 |         int mid = l + r >> 1;
      |                   ~~^~~
port_facility.cpp: In member function 'int PST::Get(int, int, int, int, int)':
port_facility.cpp:23:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   23 |         int mid = l + r >> 1;
      |                   ~~^~~
port_facility.cpp: In function 'int main()':
port_facility.cpp:44:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   44 |             int mid = l + r >> 1;
      |                       ~~^~~

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