Compilare: user.cpp: In function ‘int bfs(int, int)’: user.cpp:16:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[q.front()].size(); i++) ~^~~~~~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:27:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] { freopen("promo.in", "r",stdin); ^ user.cpp:28:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("promo.out", "w",stdout); ^ user.cpp:30:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &m, &k); ^ user.cpp:32:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^