Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:63:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k = 0; k < o[j].size(); k++) ^ user.cpp:80:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < o[i].size(); j++) ^ In file included from /usr/include/c++/4.8/algorithm:62:0, from user.cpp:4: /usr/include/c++/4.8/bits/stl_algo.h: In instantiation of ‘_RandomAccessIterator std::__unguarded_partition(_RandomAccessIterator, _RandomAccessIterator, const _Tp&, _Compare) [with _RandomAccessIterator = std::vector<int>*; _Tp = std::vector<int>; _Compare = bool (*)(std::vector<int>&, std::vector<int>&)]’: /usr/include/c++/4.8/bits/stl_algo.h:2319:78: required from ‘_RandomAccessIterator std::__unguarded_partition_pivot(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = std::vector<int>*; _Compare = bool (*)(std::vector<int>&, std::vector<int>&)]’ /usr/include/c++/4.8/bits/stl_algo.h:2360:62: required from ‘void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size, _Compare) [with _RandomAccessIterator = std::vector<int>*; _Size = int; _Compare = bool (*)(std::vector<int>&, std::vector<int>&)]’ /usr/include/c++/4.8/bits/stl_algo.h:5513:44: required from ‘void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = std::vector<int>*; _Compare = bool (*)(std::vector<int>&, std::vector<int>&)]’ user.cpp:75:26: required from here /usr/include/c++/4.8/bits/stl_algo.h:2287:35: error: invalid initialization of reference of type ‘std::vector<int>&’ from expression of type ‘const std::vector<int>’ while (__comp(*__first, __pivot)) ^ /usr/include/c++/4.8/bits/stl_algo.h:2290:34: error: invalid initialization of reference of type ‘std::vector<int>&’ from expression of type ‘const std::vector<int>’ while (__comp(__pivot, *__last)) ^