i think there is some issue with while loop but i cannot find it, because of which i cannot even clear the sample testcases. Kindly Help !
A short gist of my logic -
Note 1 : IF a country gets cured then i remove that countryās population from multiset.
Note 2 : if the multiset is empty, just print out the days.
if X is greater than or equal to most populated country then answer is number of countries present in my multiset.
else two conditions arise -
if there is a value in multiset (each set element representing a countryās population) which falls in the range [x,2x] inclusive then, we know that answer is days = days + current set.size (as from this day we will need only as many days as many countries are left to be cured)
Else if no element of the set falls within the range [x,2x] then we will use two times of, cures used on previous day, to cure the country with the largest population currently present in multiset. and also update the x for next day
i.e x = 2*x
what is this flag ? i have no idea what is this and from where to learn to use this. from where can i learn about this ? will that codeforces link guide me properly ?
with this flag i m getting something like this but i cannot figure out why ?
prog.cpp: In function āstd::basic_ostream<_CharT, _Traits>& std::flush(std::basic_ostream<_CharT, _Traits>&) [with _CharT = char; _Traits = std::char_traits<char>]ā:
prog.cpp:150:1: internal compiler error: Segmentation fault
}
^
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-6/README.Bugs> for instructions.
You can, but youāll get much less useful information about whatās going on, and wonāt be able to use a debugger. I wouldnāt bother, personally: just sort out your local build environment and use that.
Can you share some syntax on how to use these flags in a c++ code ?
And also if possible a small example of code along with with the output error message, so that i can learn how to use this.
Also i donāt know anything about pragma.
[simon@simon-laptop][13:36:04]
[~/devel/hackerrank/otherpeoples]>g++ rudyiscrazy1-DRCHEF.cpp -g3 -O3 -Wall -Wextra -DONLINE_JUDGE -D_GLIBCXX_DEBUG -fsanitize=undefined -ftrapv
rudyiscrazy1-DRCHEF.cpp: In function āint main()ā:
rudyiscrazy1-DRCHEF.cpp:41:14: warning: ignoring return value of āint scanf(const char*, ...)ā, declared with attribute warn_unused_result [-Wunused-result]
scanf("%d",&N) ;
~~~~~^~~~~~~~~
rudyiscrazy1-DRCHEF.cpp:42:15: warning: ignoring return value of āint scanf(const char*, ...)ā, declared with attribute warn_unused_result [-Wunused-result]
scanf ("%ld",&x) ;
~~~~~~^~~~~~~~~~
rudyiscrazy1-DRCHEF.cpp:53:19: warning: ignoring return value of āint scanf(const char*, ...)ā, declared with attribute warn_unused_result [-Wunused-result]
scanf ("%ld",&val) ;
~~~~~~^~~~~~~~~~~~
[simon@simon-laptop][13:36:12]
[~/devel/hackerrank/otherpeoples]>echo "3
> 5 5
> 1 2 3 4 5
> 5 1
> 40 30 20 10 50
> 3 10
> 20 1 110" | ./a.out
rudyiscrazy1-DRCHEF.cpp:122:41: runtime error: signed integer overflow: -6148914691236495360 * 2 cannot be represented in type 'long int'
rudyiscrazy1-DRCHEF.cpp:14:27: runtime error: signed integer overflow: 5764607523034234880 * 2 cannot be represented in type 'long int'
/usr/include/c++/7/debug/safe_iterator.h:327:
Error: attempt to decrement a dereferenceable (start-of-sequence) iterator.
Objects involved in the operation:
iterator "this" @ 0x0x7ffcb476d060 {
type = __gnu_debug::_Safe_iterator<std::_Rb_tree_const_iterator<long>, std::__debug::multiset<long, std::less<long>, std::allocator<long> > > (mutable iterator);
state = dereferenceable (start-of-sequence);
references sequence with type 'std::__debug::multiset<long, std::less<long>, std::allocator<long> >' @ 0x0x7ffcb476d300
}
Aborted (core dumped)
If you canāt do that, you can make sure the first two lines in your .cpp file are:
#define _GLIBCXX_DEBUG // Iterator safety; out-of-bounds access for Containers, etc.
#pragma GCC optimize "trapv" // abort() on (signed) integer overflow.
(this doesnāt include the -fsanitize=undefined flag, alas - not sure how to do that), but as I mentioned, this seems to give much less useful information, so Iād stick with compiling locally and passing the flags to gcc.
hey i got few things cleared from your local compiling ! so there are two places where i am getting int overflow and at one place i m decrementing a iterator pointing to start of the container.
but there is new problem eating my head - #pragma GCC optimize ātrapvā
does this give an error message similar to the fashion in which we get when we use #define _GLIBCXX_DEBUG
or it just tells us a SIGBART error
herre is what i get when i compiled my code with just #pragma GCC optimize ātrapvā
That just gives SIGABRT on signed integer overlow. Itās mainly useful for deciding whether your WA is due to integer overflow or not; -fsanitize=undefined is probably better for local debugging.
okay things are getting clearer, Thnx a lot !
By the way, what does this part means, " ignoring return value of āint scanf(const char*, ā¦)ā, declared with attribute warn_unused_result [-Wunused-result] ", while you are compiling ??
