Submission #329481

#	Time	Username	Problem	Language	Result	Execution time	Memory
329481		mihai145	Martian DNA (IOI16_dna)	C++14	100 / 100	15 ms	492 KiB

dna

#include "dna.h"

#include <cstdlib>
#include <random>

int failureCt = 19;

std::string analyse(int n, int t) {

    std::string randomSuffix = "";
    int failures = 0;

    while(failures < failureCt && randomSuffix.size() < n) {
        int rnd = rand() % 2;

        if(rnd == 0) {
            bool res = make_test(randomSuffix + '0');
            if(res == true) {
                randomSuffix += '0';
                failures = 0;
            } else {
                randomSuffix += '1';
                failures++;
            }
        } else {
            bool res = make_test(randomSuffix + '1');
            if(res == true) {
                randomSuffix += '1';
                failures = 0;
            } else {
                randomSuffix += '0';
                failures++;
            }
        }
    }

    std::string root = "", rnd = "";

    for(int i = 0; i < (int)randomSuffix.size(); i++) {
        if(i + failures >= (int)randomSuffix.size()) {
            rnd += randomSuffix[i];
        } else {
            root += randomSuffix[i];
        }
    }

    int st = 0, dr = (int)rnd.size(), sol = 0;

    while(st <= dr) {
        int mid = (st + dr) >> 1;

        std::string toQ = root;
        for(int i = 0; i < mid; i++)
            toQ += rnd[i];

        bool res = make_test(toQ);

        if(res == true) {
            sol = mid;
            st = mid + 1;
        } else {
            dr = mid - 1;
        }
    }

    for(int i = 0; i < sol; i++)
        root += rnd[i];

    while((int)root.size() < n) {
        bool res = make_test('0' + root);
        if(res == true) {
            root = '0' + root;
        } else {
            root = '1' + root;
        }
    }

    return root;
}

Compilation message (stderr)

dna.cpp: In function 'std::string analyse(int, int)':
dna.cpp:13:55: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   13 |     while(failures < failureCt && randomSuffix.size() < n) {
      |                                   ~~~~~~~~~~~~~~~~~~~~^~~
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