Submission #743716

#TimeUsernameProblemLanguageResultExecution timeMemory
743716pls33Highway Tolls (IOI18_highway)C++17
0 / 100
20 ms1400 KiB
#include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> #ifndef _AAAAAAAAA #include "highway.h" #else void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B); long long ask(const std::vector<int> &w); void answer(int s, int t); #endif using namespace std; using namespace __gnu_pbds; #pragma region dalykai template <typename F> void _debug(F f) { f(); } #ifndef _AAAAAAAAA #define debug(x) #else #define debug(x) _debug(x) #endif using p32 = pair<int, int>; using p32u = pair<uint32_t, uint32_t>; using p64 = pair<int64_t, int64_t>; using p64u = pair<uint64_t, uint64_t>; using vi16 = vector<int16_t>; using vi16u = vector<uint16_t>; using vi32 = vector<int>; using vi32u = vector<uint32_t>; using vi64 = vector<int64_t>; using vi64u = vector<uint64_t>; using vp32 = vector<p32>; using vp32u = vector<p32u>; using vp64 = vector<p64>; using vp64u = vector<p64u>; using vvi32 = vector<vi32>; using vvi32u = vector<vi32u>; using vvi64 = vector<vi64>; using vvi64u = vector<vi64u>; using vvp32 = vector<vp32>; using vvp32u = vector<vp32u>; using vvp64 = vector<vp64>; using vvp64u = vector<vp64u>; using f80 = long double; #pragma endregion using state_t = bitset<size_t(13 * 1e4)>; // kelinta briauna keicia trumpiausia kelia?? int find_blocking_edge(int64_t cost, int edge_count) { vi32 query(edge_count); int low = 0, high = edge_count - 1; while (low != high) { int mid = (low + high) / 2; for (int i = 0; i < edge_count; i++) { query[i] = i <= mid; } int64_t new_cost = ask(query); if (new_cost != cost) { high = mid; } else { low = mid + 1; } } return low; } void find_bfs_order(int start, int blocked, vvp32 &adj, vp32 &order, vi32 &distance) { queue<int> q; state_t visited; q.push(start); distance[start] = 0; visited[start] = true; visited[blocked] = true; while (!q.empty()) { int cur = q.front(); q.pop(); for (auto &[next, index] : adj[cur]) { if (visited[next]) { continue; } order.emplace_back(index, next); q.push(next); visited[next] = true; distance[next] = distance[cur] + 1; } } } int find_end_edge(vp32 &order, int64_t cost, int edge_count) { vi32 query(edge_count); int low = -1, high = (int)order.size() - 1; while (low != high) { int mid = (low + high + 1) / 2; // blokuojam ne medzio, o nereikalingas briaunas fill(query.begin(), query.end(), 1); for (int i = 0; i < mid; i++) { query[order[i].first] = 0; } int64_t new_cost = ask(query); if (new_cost != cost) { low = mid; } else { high = mid - 1; } } return low; } void find_pair(int n, std::vector<int> u, std::vector<int> v, int A, int B) { B = B; const int edge_count = (int)u.size(); vvp32 adj(n); for (int i = 0; i < edge_count; i++) { // printf("%d -- %d [label=\"%d\"]\n", U[i], V[i], i); int a = u[i], b = v[i]; adj[a].emplace_back(b, i); adj[b].emplace_back(a, i); } vi32 sample(u.size()); int64_t cost = ask(sample); int initial = find_blocking_edge(cost, edge_count); int a = u[initial], b = v[initial]; if (cost == A) { answer(a, b); return; } int l = -1, r = -1; for (int i = 0; i < 2; i++) { vp32 order; vi32 distance(n, INT_MAX); find_bfs_order(a, b, adj, order, distance); if (!order.size()) { l = a; swap(l, r); swap(a, b); continue; } int end = find_end_edge(order, (cost / A) * B, edge_count); l = (end == -1) ? a : order[end].second; swap(l, r); swap(a, b); } answer(l, r); } #ifdef _AAAAAAAAA namespace { constexpr int MAX_NUM_CALLS = 100; constexpr long long INF = 1LL << 61; int N, M, A, B, S, T; std::vector<int> U, V; std::vector<std::vector<std::pair<int, int>>> graph; bool answered, wrong_pair; int num_calls; int read_int() { int x; if (scanf("%d", &x) != 1) { fprintf(stderr, "Error while reading input\n"); exit(1); } return x; } void wrong_answer(const char *MSG) { printf("Wrong Answer: %s\n", MSG); exit(0); } } // namespace long long ask(const std::vector<int> &w) { if (++num_calls > MAX_NUM_CALLS) { wrong_answer("more than 100 calls to ask"); } if (w.size() != (size_t)M) { wrong_answer("w is invalid"); } for (size_t i = 0; i < w.size(); ++i) { if (!(w[i] == 0 || w[i] == 1)) { wrong_answer("w is invalid"); } } std::vector<bool> visited(N, false); std::vector<long long> current_dist(N, INF); std::queue<int> qa, qb; qa.push(S); current_dist[S] = 0; while (!qa.empty() || !qb.empty()) { int v; if (qb.empty() || (!qa.empty() && current_dist[qa.front()] <= current_dist[qb.front()])) { v = qa.front(); qa.pop(); } else { v = qb.front(); qb.pop(); } if (visited[v]) { continue; } visited[v] = true; long long d = current_dist[v]; if (v == T) { return d; } for (auto e : graph[v]) { int vv = e.first; int ei = e.second; if (!visited[vv]) { if (w[ei] == 0) { if (current_dist[vv] > d + A) { current_dist[vv] = d + A; qa.push(vv); } } else { if (current_dist[vv] > d + B) { current_dist[vv] = d + B; qb.push(vv); } } } } } return -1; } void answer(int s, int t) { if (answered) { wrong_answer("answered not exactly once"); } printf("\n----------------\ngautas atsakymas: %d ir %d\n", s, t); if (!((s == S && t == T) || (s == T && t == S))) { wrong_pair = true; } answered = true; } int main() { freopen("greitkeliai.in", "r", stdin); #ifndef __linux__ atexit([]() { freopen("con", "r", stdin); system("pause"); }); #endif N = read_int(); M = read_int(); A = read_int(); B = read_int(); S = read_int(); T = read_int(); U.resize(M); V.resize(M); graph.assign(N, std::vector<std::pair<int, int>>()); for (int i = 0; i < M; ++i) { U[i] = read_int(); V[i] = read_int(); graph[U[i]].push_back({V[i], i}); graph[V[i]].push_back({U[i], i}); } answered = false; wrong_pair = false; num_calls = 0; find_pair(N, U, V, A, B); if (!answered) { wrong_answer("answered not exactly once"); } if (wrong_pair) { wrong_answer("{s, t} is wrong"); } printf("Accepted: %d\n", num_calls); return 0; } #endif

Compilation message (stderr)

highway.cpp:15: warning: ignoring '#pragma region dalykai' [-Wunknown-pragmas]
   15 | #pragma region dalykai
      | 
highway.cpp:50: warning: ignoring '#pragma endregion ' [-Wunknown-pragmas]
   50 | #pragma endregion
      |
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