Submission #503699

#	Time	Username	Problem	Language	Result	Execution time	Memory
503699		cristi_a	Combo (IOI18_combo)	C++17	0 / 100	1 ms	328 KiB

combo

#include <iostream>
#include <string.h>
#include "combo.h"
using namespace std;

string guess_sequence(int N) {
    char lets[4];
    strcpy(lets,"ABXY");
    string rez = "";
    if(press("AB")) rez = press("A") ? "A" : "B";
    else rez = press("X") ? "X" : "Y";

    for(int i=0; i<4; i++)
        if(lets[i]==rez[0]) {
            strcpy(lets+i,lets+i+1);
            break;
        }

    for(int i=1; i<N; i++) {
        if(i==N-1) {
            if(press(rez+lets[0])==N) rez = rez + lets[0];
            else if(press(rez+lets[1])==N) rez = rez + lets[1];
            else rez = rez + lets[2];
        }
        else {
            string temp = rez + lets[1] + rez + lets[0] + lets[0] + rez + lets[0] + lets[1] + rez + lets[0] + lets[2];
            int w = press(temp);
            if(w == i+1) rez = rez + lets[1];
            else if(w==i+2) rez = rez + lets[0];
            else rez = rez + lets[2];
        }
    }
    return rez;
}

Compilation message (stderr)

In file included from /usr/include/string.h:495,
                 from combo.cpp:2:
In function 'char* strcpy(char*, const char*)',
    inlined from 'std::string guess_sequence(int)' at combo.cpp:8:11:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:90:33: warning: 'char* __builtin___strcpy_chk(char*, const char*, long unsigned int)' writing 5 bytes into a region of size 4 [-Wstringop-overflow=]
   90 |   return __builtin___strcpy_chk (__dest, __src, __bos (__dest));
      |          ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:7:10: note: at offset 0 to object 'lets' with size 4 declared here
    7 |     char lets[4];
      |          ^~~~
In file included from /usr/include/string.h:495,
                 from combo.cpp:2:
In function 'char* strcpy(char*, const char*)',
    inlined from 'std::string guess_sequence(int)' at combo.cpp:8:11:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:90:33: warning: 'void* __builtin___memcpy_chk(void*, const void*, long unsigned int, long unsigned int)' forming offset 4 is out of the bounds [0, 4] of object 'lets' with type 'char [4]' [-Warray-bounds]
   90 |   return __builtin___strcpy_chk (__dest, __src, __bos (__dest));
      |          ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:7:10: note: 'lets' declared here
    7 |     char lets[4];
      |          ^~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 95