# | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
104712 | 2019-04-09T02:17:16 Z | turbat | Highway Tolls (IOI18_highway) | C++14 | 0 ms | 0 KB |
#include <cstdio> #include <cstdlib> #include <cstring> #include <queue> #include <utility> #include <vector> #include "highway.h" 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"); } if (!((s == S && t == T) || (s == T && t == S))) { wrong_pair = true; } answered = true; } int main() { 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; }