Compilare: main.cpp: In function 'int bfs(int)': main.cpp:23:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<arcs[current_node].size(); ++i) { ~^~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:38:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("darb.in", "r", stdin); ^ main.cpp:39:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("darb.out", "w", stdout); ^ main.cpp:42:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:46:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^