Compilare: main.cpp: In function 'void bfs(int)': main.cpp:28:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < fr[nod].size(); i++) ~~^~~~~~~~~~~~~~~~ main.cpp:31:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j < fr[a].size(); j++) ~~^~~~~~~~~~~~~~ main.cpp:35:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = 0; k < nfr[nod].size(); k++) ~~^~~~~~~~~~~~~~~~~ main.cpp:43:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k == nfr[nod].size()) ~~^~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:67:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j < nfr[i].size(); j++) ~~^~~~~~~~~~~~~~~ main.cpp:51:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fof.in", "r", stdin); ^ main.cpp:52:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fof.out", "w", stdout); ^ main.cpp:54:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:57:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^