Submission #1238737

#	Time	Username	Problem	Language	Result	Execution time	Memory
1238737		k1r1t0	Prisoner Challenge (IOI22_prison)	C++20	100 / 100	7 ms	1096 KiB

prison

#include <bits/stdc++.h>

using namespace std;

const int N = 5000;
vector<int> cnt = {2, 3, 3, 3, 3, 2, 2, 2}, sz = {5000, 2499, 833, 277, 92, 30, 14, 6, 2};

int get(int n, int k) {
	for (int i = 1; i <= k; i++) {
		if (n <= 1) return 1;
		n -= 2;
		n %= sz[i];
		n++;
	}
	return n;
}

// 0 - A
// 1 - B

vector<vector<int>> devise_strategy(int _) {
	int m = (int) cnt.size();
	vector<vector<int>> vec;
	vector<int> cur(N + 1);
	cur[0] = 0;
	for (int i = 1; i <= N; i++) {
		int val = get(i, 0);
		if (val == 1) cur[i] = -1;
		else if (val == sz[0]) cur[i] = -2;
		else {
			int id = (val - 2) / sz[1];
			cur[i] = id + 1;
		}
	}
	vec.push_back(cur);
	for (int d = 0; d < m; d++) {
		int k = (d & 1) ^ 1;
		int our = (k == 0 ? -1 : -2);
		int their = -3 - our;
		int new_sz = vec.size() + cnt[d];
		for (int their_id = 0; their_id < cnt[d]; their_id++) {
			vector<int> cur(N + 1);
			cur[0] = k;
			for (int i = 1; i <= N; i++) {
				int val = get(i, d);
				if (val == 1) cur[i] = our;
				else if (val == sz[d]) cur[i] = their;
				else {
					int our_id = (val - 2) / sz[d + 1];
					if (our_id < their_id) cur[i] = our;
					else if (our_id > their_id) cur[i] = their;
					else {
						int val_next = get(i, d + 1);
						if (val_next == 1) cur[i] = our;
						else if (val_next == sz[d + 1]) cur[i] = their;
						else {
							if (d + 2 > m) {
								cur[i] = -1;
								continue;
							}
							our_id = (val_next - 2) / sz[d + 2];
							cur[i] = our_id + new_sz;
						}
					}
				}
			}
			vec.push_back(cur);
		}
	}
	for (auto &cur : vec) {
		cur.resize(_ + 1);
		for (int &j : cur)
			j = clamp(j, -2, (int) vec.size() - 1);
	}
	return vec;
}


























/*
static constexpr int kNumPrisoners = 500;

static void invalid_strategy(std::string message) {
  printf("%s\n", message.c_str());
  exit(0);
}

int main() {
  int N;
  assert(1 == scanf("%d", &N));

  std::vector<std::vector<int>> strategy = devise_strategy(N);
  if (strategy.size() == 0) {
    invalid_strategy("s is an empty array");
  }
  int x = strategy.size() - 1;
  for (int i = 0; i <= x; ++i) {
    if (static_cast<int>(strategy[i].size()) != N + 1) {
      invalid_strategy("s[i] contains incorrect length");
    }
    if (strategy[i][0] < 0 || strategy[i][0] > 1) {
      invalid_strategy("First element of s[i] is non-binary"); 
    }
    for (int j = 1; j <= N; ++j) {
      if (strategy[i][j] < -2 || strategy[i][j] > x) {
        invalid_strategy("s[i][j] contains incorrect value");
      }
    }
  }

  FILE *log_file = fopen("log.txt","w");

  for (int A = 1; A <= N; A++)
  for (int B = 1; B <= N; B++) if (A != B) {
    bool answer = false;
    int whiteboard = 0;
    for (int i = 0; i < kNumPrisoners && !answer; ++i) {
      int check = strategy[whiteboard][0];
      whiteboard = strategy[whiteboard][check == 0 ? A : B];
      if (whiteboard < 0) {
        if ((whiteboard == -2 && B > A) ||
			(whiteboard == -1 && B < A)) {
			cout << "BAD: " << A << ' ' << B;
			return 0;
		}
        answer = true;
        printf("%c\n", "BA"[whiteboard + 2]);
      } else {
        if (i > 0) {
          fprintf(log_file, " ");
        }
        fprintf(log_file, "%d", whiteboard);
      }
    }
    if (!answer) {
      printf("X\n");
      return 0;
    }
    fprintf(log_file, "\n");
    fflush(log_file);
  }
}
//*/

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 90 / 90