Submission #844844

#TimeUsernameProblemLanguageResultExecution timeMemory
844844hamerinSalesman (IOI09_salesman)C++17
38 / 100
3084 ms65536 KiB
#include <bits/stdc++.h> #pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") using namespace std; using li = long long; using ld = long double; using pi = pair<int, int>; using pli = pair<li, li>; #define all(c) c.begin(), c.end() #define prec(n) setprecision(n) << fixed template <typename T> class SegTree { public: uint N; vector<T> vl; explicit SegTree(uint _N) : N(_N), vl(N << 2, numeric_limits<T>::min() / T(2)) {} void update(uint s, uint e, uint n, uint t, T x) { if (t < s || e < t) return; if (s == e) { vl[n] = x; return; } uint m = (s + e) >> 1, k = n << 1; update(s, m, k, t, x); update(m + 1, e, k | 1, t, x); vl[n] = max(vl[k], vl[k | 1]); } T query(uint s, uint e, uint n, uint l, uint r) { if (r < s || e < l) return numeric_limits<T>::min() / T(2); if (l <= s && e <= r) return vl[n]; uint m = (s + e) >> 1, k = n << 1; return max(query(s, m, k, l, r), query(m + 1, e, k | 1, l, r)); } inline void update(uint t, T x) { update(0, N - 1, 1, t, x); } inline T query(uint l, uint r) { return query(0, N - 1, 1, l, r); } }; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); int N, U, D, S; cin >> N >> U >> D >> S; vector<int> locs(1, S), days({0, 500001}); vector<tuple<int, int, int>> markets; markets.emplace_back(0, S, 0); markets.emplace_back(500001, S, 0); for (int i = 0; i < N; i++) { int T, L, M; cin >> T >> L >> M; markets.emplace_back(T, L, M); locs.emplace_back(L); days.emplace_back(T); } sort(all(days)), days.erase(unique(all(days)), days.end()); sort(all(locs)), locs.erase(unique(all(locs)), locs.end()); vector<vector<pi>> marketsByDay(days.size()); for (auto [T, L, M] : markets) marketsByDay[lower_bound(all(days), T) - days.begin()].emplace_back(L, M); for (auto& day : marketsByDay) sort(all(day)); bool init = true; vector<int> revenues(locs.size(), numeric_limits<int>::min() / 2); SegTree<int> upper((uint)locs.size()), lower((uint)locs.size()); for (auto& marketsOfDay : marketsByDay) { if (init) { const int Lc = lower_bound(all(locs), marketsOfDay[0].first) - locs.begin(); upper.update(Lc, -U * marketsOfDay[0].first); lower.update(Lc, D * marketsOfDay[0].first); init = false; continue; } vector<int> idxs(marketsByDay.size()); vector<int> queryResults(marketsByDay.size()); for (int i = 0; i < (int)marketsOfDay.size(); i++) { const auto [L, M] = marketsOfDay[i]; const int Lc = lower_bound(all(locs), L) - locs.begin(); idxs[i] = Lc; queryResults[i] = max(upper.query(Lc, (uint)locs.size() - 1) + U * L, lower.query(0, Lc) - D * L); } optional<pi> last = nullopt; for (int i = 0; i < (int)marketsOfDay.size(); i++) { const auto [L, M] = marketsOfDay[i]; const int Lc = idxs[i]; int R = max(queryResults[i], last ? last->first - D * (L - last->second) : numeric_limits<int>::min()) + M; revenues[Lc] = max(revenues[Lc], R); last = {R, L}; } last = nullopt; for (int i = (int)marketsOfDay.size() - 1; i >= 0; i--) { const auto [L, M] = marketsOfDay[i]; const int Lc = idxs[i]; int R = max(queryResults[i], last ? last->first - U * (last->second - L) : numeric_limits<int>::min()) + M; revenues[Lc] = max(revenues[Lc], R); last = {R, L}; } for (int i = 0; i < (int)marketsOfDay.size(); i++) { const auto [L, M] = marketsOfDay[i]; const int Lc = idxs[i]; upper.update(Lc, revenues[Lc] - U * L); lower.update(Lc, revenues[Lc] + D * L); } } cout << revenues[lower_bound(all(locs), S) - locs.begin()] << '\n'; return 0; }

Compilation message (stderr)

salesman.cpp: In function 'int main()':
salesman.cpp:121:30: warning: 'last.std::pair<int, int>::first' may be used uninitialized in this function [-Wmaybe-uninitialized]
  121 |                         last ? last->first - U * (last->second - L) : numeric_limits<int>::min()) +
      |                         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
salesman.cpp:121:64: warning: 'last.std::pair<int, int>::second' may be used uninitialized in this function [-Wmaybe-uninitialized]
  121 |                         last ? last->first - U * (last->second - L) : numeric_limits<int>::min()) +
      |                                                  ~~~~~~~~~~~~~~^~~~
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