Submission #632916

#	Time	Username	Problem	Language	Result	Execution time	Memory
632916		MojoLake	Prisoner Challenge (IOI22_prison)	C++17	80 / 100	14 ms	1028 KiB

prison

#include <iostream>
#include <vector>


using namespace std;

const int max_dig = 7;
int x = 22;


int get_trit(int num, int j){
  while(--j>=0)num/=3;
  return num%3;
}


int compare(int i, int j){

  int d = (i+2) / 3;
  int prev_trit = (i+2) % 3;
  
  int prev_pos = max_dig - d + 1;
  int cur_trit = get_trit(j, prev_pos);

  bool a = d % 2 == 0;

  if(prev_trit != cur_trit){
    return (a == (cur_trit > prev_trit)) ? -2 : -1;
  }

  if(i == 22){
    return ((cur_trit == 2) == a) ? -2 : -1;
  }

  int cur_pos = max_dig - d;
  int now_trit = get_trit(j, cur_pos);

  
  if(cur_pos == 0){
    if(now_trit == 2){
      return a ? -2 : -1;
    }
    if(now_trit == 0){
      return a ? -1 : -2;
    }
    return 22;
  }


  return 3 * (d + 1) + now_trit - 2;
}




vector<vector<int>> devise_strategy(int n){

  vector<vector<int>> ret(x + 1, vector<int>(n+1));

  for(int i = 0; i <= x; ++i){
    for(int j = 0; j <= n; ++j){

      if(j == 0){
        ret[i][j] = ((i+2)/3)%2 != 0;
        continue;
      }

      if(i == 0){
        
        int trit = get_trit(j, max_dig);
        ret[i][j] = 1 + trit;
        continue;
      }

      ret[i][j] = min(x, compare(i, j));
 
    }
  }

  ret[0][0] = 0;

  return ret;
}

//compare in base 3
//3**8 > 5000
//therefore need 8 trits for info
//start from highest 
//open A
//mark value of highest trit (0, 1, 2)
//3 * 7 + 2 = 23

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 70 / 90