Compilare: user.cpp: In function ‘void bfs()’: user.cpp:20:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0 ; j < G[P[i]].size() && !ok;j++) ^ user.cpp: In function ‘int main()’: user.cpp:29:13: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(in); ^ user.cpp:30:14: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(out); ^ user.cpp:31:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&X,&Y); ^ user.cpp:33:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&i,&j,&c); ^