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Look at these submissions:
They have one different that is using:
for(int c:vec)
instead of:
for(int j=0;j<vec.size();j++){
int c = vec[j];
...
}
one get Runtime and other one is Accepted.
I think that is happen because I change the size of my vector in the "for" However the size of it will be constant after each step.
Can I anyone explain? Tnks a lot.
I guess the first for stands for this:
for (auto it = v.begin(); it != v.end(); ++it)
Though, if it == v.end() — 1, you delete last element in vector and then make ++it, iterator will never become equal to v.end().
Changing the size may cause reallocation of memory for capacity increasing. As the result, iterators, that are used in range-based for loop, become invalid.
I'm not sure how vector iterators are realised in gcc, but theoretically they can handle it.
They are just a pointers, so they cant. Not only in gcc, but in VC++ and Clang too.