Submission #641097

#	Time	Username	Problem	Language	Result	Execution time	Memory
641097		quocnguyen1012	Cave (IOI13_cave)	C++14	100 / 100	1527 ms	668 KiB

cave

#include "bits/stdc++.h"
#include "cave.h"

using namespace std;

const int maxn = 5005;

int a[maxn], mark[maxn], b[maxn], match[maxn];

void exploreCave(int N) {
  for (int door = 0; door < N; ++door) {
    for (int i = 0; i < N; ++i) {
      if (mark[i]) b[i] = a[i];
      else b[i] = 0;
    }

    int res = tryCombination(b);
    if (res == -1) res = N;
    //cerr << res << '\n';
    const auto ask = [&](int pivot, int v) {
      for (int i = 0; i < N; ++i) {
        if (mark[i]) b[i] = a[i];
        else b[i] = 0;
      }
      for (int i = 0; i <= pivot; ++i) {
        if (not mark[i])
          b[i] = (v ^ 1);  
      }
      for (int i = pivot + 1; i < N; ++i) {
        if (not mark[i]) b[i] = v;
      }

      int r = tryCombination(b);
     // cerr << "return " << r << '\n';
      if (r == -1) r = N;
      return (r > door);
    };

    int l = 0, r = N - 1, mid;
    while (l <= r) {
      mid = (l + r) / 2;
      if (not ask(mid, (res <= door))) r = mid - 1;
      else l = mid + 1;
    }
    //cerr << "pos " << r << '\n';
    if (door == 2) {
      for (int i = 0; i < N; ++i) {
     //   cerr << "check " << i << ' ' << ask(i, (res <= door)) << '\n';
      }
    }
    if (res > door) {
      /// val = 0
      a[l] = 0;
      mark[l] = 1; match[l] = door;
    } else {
      /// val = 1
      a[l] = 1;
      mark[l] = 1; match[l] = door;
    }
  }
  answer(a, match);
}

#ifdef LOCAL
int main() {
  init();
  exploreCave(N);
}
#endif

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