cp/cses/sorting-and-searching/traffic-lights.cc
2025-03-05 16:22:13 -05:00

139 lines
2.9 KiB
C++

#include <bits/stdc++.h> // {{{
// https://codeforces.com/blog/entry/96344
#pragma GCC optimize("O2,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
using namespace std;
template <typename T>
[[nodiscard]] static T MIN() {
return std::numeric_limits<T>::min();
}
template <typename T>
[[nodiscard]] static T MAX() {
return std::numeric_limits<T>::max();
}
template <typename T>
[[nodiscard]] static T sc(auto&& x) {
return static_cast<T>(x);
}
template <typename T>
[[nodiscard]] static T sz(auto&& x) {
return static_cast<T>(x.size());
}
#define prln(...) std::println(__VA_ARGS__)
#define pr(...) std::print(__VA_ARGS__)
#ifdef LOCAL
#define dbgln(...) std::println(__VA_ARGS__)
#define dbg(...) std::print(__VA_ARGS__)
#endif
using ll = long long;
using ld = long double;
template <typename T>
using ve = std::vector<T>;
template <typename T, size_t N>
using ar = std::array<T, N>;
template <typename T1, typename T2>
using pa = std::pair<T1, T2>;
template <typename... Ts>
using tu = std::tuple<Ts...>;
template <typename... Ts>
using dq = std::deque<Ts...>;
template <typename... Ts>
using qu = std::queue<Ts...>;
template <typename... Ts>
using pq = std::priority_queue<Ts...>;
template <typename... Ts>
using st = std::stack<Ts...>;
#define ff first
#define ss second
#define eb emplace_back
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
// }}}
// NOTE: i'm getting to the point where more complex dsa
// indeed may be needed
// I faded out like "no, no way i need two DSA", even though
// a) that would def work, might as well
// NOTE: do not know the apis
void solve() {
int n, q;
cin >> n >> q;
ve<int> lights(q);
set<int> pts{0, n};
for (auto& e : lights) {
cin >> e;
pts.insert(e);
}
// NOTE: this was horrible
int maximum = 0;
int last = 0;
for (int x : pts) {
maximum = max(maximum, x - last);
last = x;
}
ve<int> ans(q, 0);
ans[q - 1] = maximum;
for (int i = q - 1; i > 0; --i) {
pts.erase(lights[i]);
auto it = pts.upper_bound(lights[i]);
int high = *it;
int low = *(--it);
maximum = max(maximum, high - low);
ans[i - 1] = maximum;
}
for (int i = 0; i < q - 1; ++i)
cout << ans[i] << ' ';
cout << ans[q - 1];
// set<int> lights{0, n};
// multiset<int> segments{n};
// int light;
// while (q--) {
// cin >> light;
//
// auto upper = lights.upper_bound(light);
// auto lower = upper;
// --lower;
//
// segments.erase(segments.find(*upper - *lower));
//
// segments.insert(*upper - light);
// segments.insert(light - *lower);
//
// lights.insert(light);
//
// cout << *segments.rbegin() << endl;
// }
}
int main() { // {{{
cin.tie(nullptr)->sync_with_stdio(false);
cin.exceptions(cin.failbit);
int t = 1;
// cin >> t;
while (t--) {
solve();
}
return 0;
}
// }}}