Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:85:26: warning: unused variable ‘val’ [-Wunused-variable] int l = i+1, r = N,mid,val; ^ In file included from /usr/include/c++/4.8/algorithm:62:0, from user.cpp:2: /usr/include/c++/4.8/bits/stl_algo.h: In instantiation of ‘_RandomAccessIterator std::__unguarded_partition(_RandomAccessIterator, _RandomAccessIterator, const _Tp&, _Compare) [with _RandomAccessIterator = std::pair<int, int>*; _Tp = std::pair<int, int>; _Compare = bool (*)(std::pair<int, int>&, std::pair<int, 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::pair<int, int>*; _Compare = bool (*)(std::pair<int, int>&, std::pair<int, 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::pair<int, int>*; _Size = int; _Compare = bool (*)(std::pair<int, int>&, std::pair<int, int>&)]’ /usr/include/c++/4.8/bits/stl_algo.h:5513:44: required from ‘void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = std::pair<int, int>*; _Compare = bool (*)(std::pair<int, int>&, std::pair<int, int>&)]’ user.cpp:38:32: required from here /usr/include/c++/4.8/bits/stl_algo.h:2287:35: error: invalid initialization of reference of type ‘std::pair<int, int>&’ from expression of type ‘const std::pair<int, int>’ while (__comp(*__first, __pivot)) ^ /usr/include/c++/4.8/bits/stl_algo.h:2290:34: error: invalid initialization of reference of type ‘std::pair<int, int>&’ from expression of type ‘const std::pair<int, int>’ while (__comp(__pivot, *__last)) ^