Submission #657161

#	Time	Username	Problem	Language	Result	Execution time	Memory
657161		dXqwq	Prisoner Challenge (IOI22_prison)	C++17	65 / 100	14 ms	1108 KiB

prison

#include<bits/stdc++.h>
#ifndef local
#include"prison.h"
#endif
using namespace std;
const int M=24;
const int pw[]={1,3,9,27,81,243,729,2187};
vector<vector<int>> devise_strategy(int N)
{
	vector<vector<int>> ans;
	vector<int> cur(N+1);
	cur[0]=0;
	for(int i=1; i<=N; ++i)
		cur[i]=22+(i/pw[7])%3;
	ans.push_back(cur);
	for(int i=0; i<=7; ++i)
		for(int j=0; j<3; ++j)
		{
			cur[0]=i&1;
			for(int k=1; k<=N; ++k)
				if((k/pw[i])%3<j) cur[k]=-cur[0]-1;
				else if((k/pw[i])%3>j) cur[k]=-(cur[0]^1)-1;
				else if(i>0) cur[k]=(i-1)*3+1+(k/pw[i-1])%3;
			ans.push_back(cur);
		}
	return ans;
}
#ifdef local
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");

  int A, B;
  while (1 == scanf("%d", &A) && A != -1) {
    assert(1 == scanf("%d", &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) {
        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");
    }
    fprintf(log_file, "\n");
    fflush(log_file);
  }
}
#endif

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 55 / 90