Compilare: main.cpp: In function 'void dfs(int)': main.cpp:16:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < ad [ node ].size () ; ++ i ) ~~^~~~~~~~~~~~~~~~~~~~~ main.cpp:15:13: warning: unused variable 'found' [-Wunused-variable] int i , found = 0 ; ^~~~~ main.cpp: In function 'int main()': main.cpp:25:45: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ( "sortaret.in" , "r" , stdin ) ; ^ main.cpp:26:47: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ( "sortaret.out" , "w" , stdout ) ; ^ main.cpp:30:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , & n , & m ) ; ^ main.cpp:34:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , & x , & y ) ; ^