Compilare: main.cpp: In function 'void bfs(int)': main.cpp:25:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[u].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:72:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] { freopen("petsoft.in", "r",stdin); ^ main.cpp:73:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("petsoft.out", "w",stdout); ^ main.cpp:75:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:77:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^