70 lines
1.2 KiB
C++
70 lines
1.2 KiB
C++
#include <bits/stdc++.h> // {{{
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// https://codeforces.com/blog/entry/96344
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#pragma GCC optimize("O2,unroll-loops")
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#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
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using namespace std;
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template <typename T>
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constexpr T MIN = std::numeric_limits<T>::min();
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template <typename T>
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constexpr T MAX = std::numeric_limits<T>::max();
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template <typename T>
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[[nodiscard]] static T sc(auto&& x) {
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return static_cast<T>(x);
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}
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template <typename T>
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[[nodiscard]] static T sz(auto&& x) {
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return static_cast<T>(x.size());
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}
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using ll = long long;
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using ld = long double;
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template <typename T>
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using vec = std::vector<T>;
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template <typename T, size_t N>
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using arr = std::array<T, N>;
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#define ff first
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#define ss second
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#define eb emplace_back
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#define pb push_back
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#define all(x) (x).begin(), (x).end()
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#define rall(x) (x).rbegin(), (x).rend()
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// }}}
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void solve() {
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int n;
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cin >> n;
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vec<pair<ll, ll>> a(n);
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for (auto& [A, b] : a)
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cin >> A >> b;
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sort(all(a), [](auto& l, auto& r) {
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return l.ss < r.ss;
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});
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ll t = a[0].ss;
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ll ans = 1;
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for (auto& [l, r] : a) {
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if (l < t) {
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continue;
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}
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t = r;
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++ans;
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}
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cout << ans << endl;
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}
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int main() { // {{{
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cin.tie(nullptr)->sync_with_stdio(false);
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solve();
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return 0;
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}
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// }}}
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