Compilare: user.cpp: In function ‘int main()’: user.cpp:23:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ^ user.cpp: In function ‘void Matrix()’: user.cpp:38:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ^ user.cpp:41:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<s.size()-i;j++) ^ user.cpp: In function ‘void Solve()’: user.cpp:60:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ^ user.cpp:62:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++){ ^ user.cpp:59:9: warning: variable ‘mx’ set but not used [-Wunused-but-set-variable] int mx=-1; ^