Submission #526151

#	Time	Username	Problem	Language	Result	Execution time	Memory
526151		fakhoury	Martian DNA (IOI16_dna)	C++14	100 / 100	13 ms	392 KiB

dna

#include "dna.h"

#include <iostream>
#include <cstdlib>
#include <string>
#include <algorithm>

using namespace std;

int find_k(int n) {
    if (!make_test("0")) return 0;

    int lo = 1, hi = n, mi;
    while(lo < hi) {
        mi = (lo + hi + 1) / 2;
        if (make_test(string(mi, '0'))) lo = mi;
        else hi = mi - 1;
    }
    return lo;
}

string guess_flipped(string s, int n) {
    while((int) s.size() < n) {
        s = "0" + s;
        if (!make_test(s)) s[0] ^= '0' ^ '1';
    }
    return s;
}

string analyse(int n, int t) {
    int k = find_k(n);

    string known = string(k, '0'), cur;
    while((int) known.size() < n) {
        cur += '1';
        if (make_test(known + cur)) {
            known += cur;
            cur.clear();
        } else {
            cur.back() = '0';
            if ((int) cur.size() == k + 1 || (int) known.size() + (int) cur.size() == n) {
                int lo = 0, hi = (int) cur.size(), mi;
                while(lo < hi) {
                    mi = (lo + hi + 1) / 2;
                    if (make_test(known + cur.substr(0, mi)))
                        lo = mi;
                    else hi = mi - 1;
                }
                known += cur.substr(0, lo);
                cur.clear();
                return guess_flipped(known, n);
            }
        }
    }

    return known;
}                       

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