Submission #320285

#	Time	Username	Problem	Language	Result	Execution time	Memory
320285		spatarel	Martian DNA (IOI16_dna)	C++17	100 / 100	12 ms	640 KiB

dna

#include "dna.h"

#include <cstdlib>

std::string letters[] = {"0", "1"};

std::string analyse(int n, int t) {
  std::string S = "";
  int doubts = 0;
  while (doubts < 19) {
    int guess = rand() % 2;
    std::string testS = letters[guess] + S;
    if (make_test(testS)) {
      S = letters[guess] + S;
      doubts = 0;
    } else {
      S = letters[1 - guess] + S;
      doubts++;
    }
  }
  
  for (int step = 16; step > 0; step /= 2) {
    if ((int)S.size() > step) {
      std::string testS = S.substr(step);
      if (!make_test(testS)) {
        S = S.substr(step);
      }
    }
  }
  S = S.substr(1);
  
  while ((int)S.size() < n) {
    int guess = rand() % 2;
    std::string testS = S + letters[guess];
    if (make_test(testS)) {
      S = S + letters[guess];
    } else {
      S = S + letters[1 - guess];
    }
  }
  return S;
}

Compilation message (stderr)

grader.cpp: In function 'bool make_test(std::string)':
grader.cpp:14:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |  for (int i = 0; i < p.size(); i++) {
      |                  ~~^~~~~~~~~~
grader.cpp:23:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |  for (int i = 1; i <= ss.size(); i++) {
      |                  ~~^~~~~~~~~~~~
grader.cpp:28:13: warning: comparison of integer expressions of different signedness: '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |   if (pr[i] == p.size()) {

• Subtask 1: 11 / 11
• Subtask 2: 25 / 25
• Subtask 3: 64 / 64