Compilare: user.cpp: In function ‘void bfs()’: user.cpp:29:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < v [last] .size () ; ++ i) ~~^~~~~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:54:37: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (cin , "%d %d" , &n , &m); ^ user.cpp:57:49: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (cin , "%d %d %d" , &a , &b , &c); ^