Submission #526143

#	Time	Username	Problem	Language	Result	Execution time	Memory
526143		fakhoury	Martian DNA (IOI16_dna)	C++14	100 / 100	11 ms	416 KiB

dna

#include "dna.h"

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

using namespace std;

string analyse(int n, int t) {
    srand(2139);

    string known, cur;
    bool flipped = false;

    auto merge = [](string& a, string b, bool flipped) {
        if (flipped) {
            reverse(b.begin(), b.end());
            return b + a;
        }
        return a + b;
    };

    auto correct = [&]() {
        if (flipped) {
            known = merge(known, cur, flipped);
            cur.clear();
            return;
        }

        int lo = 0, hi = (int) cur.size(), mi;
        while(lo < hi) {
            mi = (lo + hi + 1) / 2;
            if (make_test(merge(known, cur.substr(0, mi), flipped)))
                lo = mi;
            else hi = mi - 1;
        }
        known = merge(known, cur.substr(0, lo), flipped);
        cur.clear();
        flipped = true;
    };

    while((int) known.size() < n) {
        cur += rand()%2 + '0';
        if (make_test(merge(known, cur, flipped))) {
            known = merge(known, cur, flipped);
            cur.clear();
        } else {
            cur.back() ^= '0' ^ '1';
        }
        if (cur.size() == 16u || (int) known.size() + (int) cur.size() == n) {
            correct();
        }
    }

    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