Compilare: user.cpp: In function ‘void bfs()’: user.cpp:25:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a[crt].size(); i++) ~~^~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:34:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sate.in", "r", stdin); ^ user.cpp:35:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sate.out", "w", stdout); ^ user.cpp:37:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i %i %i", &n, &m, &x, &y); ^ user.cpp:41:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i %i", &i, &j, &D); ^