Compilare: user.cpp: In function ‘bool solve(int)’: user.cpp:21:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( poz == s.size() && D.size() == 0 ) ^ user.cpp:23:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( poz == s.size() && D.size() != 0 ) ^ user.cpp:29:45: warning: array subscript has type ‘char’ [-Wchar-subscripts] for( int i = 0 ; i < stabile[ D.front() ].size() ; i++ ) ^ user.cpp:29:52: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0 ; i < stabile[ D.front() ].size() ; i++ ) ^ user.cpp:31:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] if( stabile[ D.front() ][ i ] == s[ poz ] ) ^ user.cpp:40:47: warning: array subscript has type ‘char’ [-Wchar-subscripts] for( int i = 0 ; i < instabile[ D.front() ].size() ; i++ ) ^ user.cpp:40:54: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0 ; i < instabile[ D.front() ].size() ; i++ ) ^ user.cpp:42:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] a = instabile[ D.front() ][ i ].f; ^ user.cpp:43:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] b = instabile[ D.front() ][ i ].s; ^ user.cpp: In function ‘int main()’: user.cpp:64:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] stabile[ c ].push_back( s2[0] ); ^ user.cpp:66:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] instabile[ c ].push_back( { s2[0],s2[1] } ); ^