Compilare: user.cpp: In function ‘void preprocess(std::pair<int, int>*, int&, int)’: user.cpp:23:9: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] int a,b; ^ user.cpp:37:23: warning: ‘a’ may be used uninitialized in this function [-Wmaybe-uninitialized] ans[abs(S[b] - S[a])] = make_pair(a + 1, b); ^