Compilare: user.cpp: In function ‘int main()’: user.cpp:30:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < S.size(); ++ i) ^ user.cpp:38:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j <= N && Cnt < Unique.size()) ^ user.cpp:45:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(Cnt == Unique.size()) Ans = min(Ans, j - i + 1); ^