Submission #762796

#	Time	Username	Problem	Language	Result	Execution time	Memory
762796		vjudge1	Fun Tour (APIO20_fun)	C++17	26 / 100	10 ms	400 KiB

fun

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "C:\GCC\debug.h"
#else
#define debug(...) void(42)
#endif

/*
int hoursRequired(int X, int Y) {
  cout << X << " " << Y << endl;
  int p;
  cin >> p;
  return p;
}
*/

int hoursRequired(int X, int Y);
int attractionsBehind(int X, int Y);

vector<int> createFunTour(int N, int Q) {
  int n = N;

  vector<vector<int>> adj(n);

  bool isBinaryTree = false;

  if (n <= 500) {
    for (int i = 0; i < n; i++) {
      for (int j = i + 1; j < n; j++) {
        if (hoursRequired(i, j) == 1) {
          adj[i].push_back(j);
          adj[j].push_back(i);
        }
      }
    }
  } else {
    isBinaryTree = true;

    vector<int> par(n, -1);

    for (int i = 1; i < n; i++) {
      int x = i;
      int y = (i - 1) / 2;
      adj[y].push_back(x);
      par[x] = y;
    }

    for (int i = 0; i < n; i++) {
      sort(adj[i].begin(), adj[i].end());
    }

    function<int(int)> GrabLeft = [&](int u) {
      int ret = u;
      for (auto v : adj[u]) {
        ret = GrabLeft(v);
        break;
      }
      return ret;
    };

    function<int(int)> GrabRight = [&](int u) {
      int ret = u;
      for (int i = (int) adj[u].size() -1; i >= 0; i--) {
        int v = adj[u][i];

        ret = GrabRight(v);
        break;
      }
      return ret;
    };

    vector<int> perm;

    for (int it = 0; ; it++) {
      if (it % 2 == 0) {
        int nxt = GrabLeft(0);
        perm.push_back(nxt);

        if (par[nxt] > -1) {
          auto ptr = find(adj[par[nxt]].begin(), adj[par[nxt]].end(), nxt);
          adj[par[nxt]].erase(ptr);
        }
      } else {
        int nxt = GrabRight(0);
        perm.push_back(nxt);

        if (par[nxt] > -1) {
          auto ptr = find(adj[par[nxt]].begin(), adj[par[nxt]].end(), nxt);
          adj[par[nxt]].erase(ptr);
        }        
      }

      if ((int) perm.size() == n) {
        break;
      }
    }

    return perm;
  }

  vector<bool> block(n);

  auto findFarthest = [&](int x) {
    vector<int> d(n, -1);
    d[x] = 0;
    queue<int> que;
    que.push(x);

    while (!que.empty()) {
      auto u = que.front();
      que.pop();

      for (auto v : adj[u]) {
        if (d[v] == -1 && !block[v]) {
          d[v] = d[u] + 1;
          que.push(v);
        }
      }
    }
    return max_element(d.begin(), d.end()) - d.begin();
  };

  int p = findFarthest(0);
  vector<int> perm;

  perm.push_back(p);
  block[p] = true;

  while ((int) perm.size() < n) {
    int nxt = findFarthest(p);
    block[nxt] = true;

    perm.push_back(nxt);
    swap(p, nxt);
  }
  return perm;
}

/*
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  return 0;
}
*/

Compilation message (stderr)

fun.cpp: In function 'std::vector<int> createFunTour(int, int)':
fun.cpp:28:8: warning: variable 'isBinaryTree' set but not used [-Wunused-but-set-variable]
   28 |   bool isBinaryTree = false;
      |        ^~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 0 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 34