QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#611798#8939. PermutationUESTC_OldEastWestTL 0ms0kbC++202.4kb2024-10-04 22:48:492024-10-04 22:48:51

Judging History

This is the latest submission verdict.

  • [2024-10-04 22:48:51]
  • Judged
  • Verdict: TL
  • Time: 0ms
  • Memory: 0kb
  • [2024-10-04 22:48:49]
  • Submitted

answer

#pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
const int N = 1e6 + 5;
const int M = 31;
const int INF = 1e9;
const double eps = 1e-8;
std::vector<std::vector<int> > dp, f;

void prep() {
  dp = f = std::vector<std::vector<int> > (N, std::vector<int> (M));

  std::function<int(int, int)> DFS = [&](int n, int m) {
    if (n <= 1) return 0;
    if (m <= -1) return INF;
    if (dp[n][m]) return dp[n][m];

    dp[n][m] = INF;
    int mid = n - n / 3;
    for (int i = std::max(1, int(0.6 * mid - 1)); i < std::min(n, int(0.7 * mid + 1)); i += int(0.1 * mid / 50) + 1) {
      int new_val = std::max(DFS(i, m - 1), DFS(n - i, m - 2) + n - i) + i;
      if (new_val < dp[n][m]) f[n][m] = i, dp[n][m] = new_val;
    }

    return dp[n][m];
  };

  for (int i = 2; i < N; ++i) {
    int k = int(1.5 * log(i) / log(2) + 1.0);
    for (int j = std::max(0, k - 3); j < k; ++j) DFS(i, j);
//    if (DFS(i, k - 1) > 2 * i || !f[i][k - 1]) std::cout << '!';
  }
//	for (int i = 0; i < N; ++i) {
//		for (int j = 0; j < M; ++j) {
//			f[i][j] = int(0.618 * i);
//		}
//	}
}

void charming() {
  int n; std::cin >> n;

  std::function<int(int, int)> Send = [&](int l, int r) {
    if (l == r) return -1;
    std::cout << "? " << l << ' ' << r << '\n';
    std::cout.flush();
    int rcv; std::cin >> rcv;
    return rcv;
  };
  
  std::function<void(int)> Answer = [&](int x) {
    std::cout << "! " << x << '\n';
    std::cout.flush();
  };

  int remain = int(1.5 * (log(n) / log(2)) + 1.0 + eps);
//  std::cout << remain << '\n';
  int l = 1, r = n, p = -1;
  while (l < r) {
    if (p == -1) p = Send(l, r), --remain;

    if (l + 1 == r) {
      if (p == l) ++l;
      break;
    }
    
    int ask_len = f[r - l + 1][remain];
    if (ask_len <= (r - l) / 2) ++ask_len;
    
//    std::cout << f[r - l + 1][remain];
    if (l + ask_len - 1 >= p) {
      int q = Send(l, l + ask_len - 1); --remain;
      if (q == p) r = l + ask_len - 1;
      else l = l + ask_len, p = -1;
    }
    else {
      int q = Send(r - ask_len + 1, r); --remain;
      if (q == p) l = r - ask_len + 1;
      else r = r - ask_len, p = -1;
    }
  }
  Answer(l);
}

signed main() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(NULL);
  std::cout.tie(NULL);
  prep();
  int t; std::cin >> t;
  while (t--) charming();
  return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 0
Time Limit Exceeded

input:

3
5
3
3
2
1

output:

? 1 5
? 1 4
? 1 3
? 1 2
! 2

result: