This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#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[45 * N], lc[45 * N], rc[45 * 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) 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;
| ~~^~~
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