Submission #988047

#	Time	Username	Problem	Language	Result	Execution time	Memory
988047		badont	Cave (IOI13_cave)	C++17	100 / 100	272 ms	600 KiB

cave

#include "cave.h"
#include <cassert>
#include <iostream>
#include <vector>

using namespace std;

void exploreCave(int N) {
  /* ... */
  int which_lock[N];
  int correct_choice[N];
  int buffer[N];

  for (int i = 0; i < N; i++)
    which_lock[i] = correct_choice[i] = buffer[i] = -1;

  for (int iter = 0; iter < N; iter++) {
    vector<int> todo;
    todo.reserve(N);
    for (int i = 0; i < N; i++) {
      if (which_lock[i] != -1) {
        buffer[i] = correct_choice[i];
      } else {
        buffer[i] = 0;
        todo.push_back(i);
      }
      assert(buffer[i] != -1);
    }
    int ret = tryCombination(buffer);
    int open_value = 1;
    if (ret == -1 or ret > iter) {
      // is open
      open_value = 0;
    }

    for (auto u : todo)
      buffer[u] = open_value;

    int lo = 0, hi = (int)todo.size() - 1;
    while (lo < hi) {
      int mid = (lo + hi + 1) >> 1;

      for (int i = 0; i < mid; i++)
        buffer[todo[i]] = (open_value ^ 1);
      for (int i = mid; i < (int)todo.size(); i++)
        buffer[todo[i]] = open_value;

      int ret = tryCombination(buffer);
#ifdef LOCAL
      cout << "buffer: ";
      for (int i = 0; i < N; i++)
        cout << buffer[i] << " ";
      cout << "\n";
      cout << "ret: " << ret << endl;
#endif

      if (ret == -1 or ret > iter)
        lo = mid;
      else
        hi = mid - 1;
    }
    which_lock[todo[lo]] = iter;
    correct_choice[todo[lo]] = open_value;
#ifdef LOCAL
    cout << "iter: " << iter << " ";
    cout << "open_value: " << open_value << " ";
    cout << "which_lock: " << todo[lo] << endl;
#endif
  }
  answer(correct_choice, which_lock);
}

• Subtask 1: 12 / 12
• Subtask 2: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 30 / 30
• Subtask 5: 24 / 24