Compilare: main.cpp: In function 'void dfs(int)': main.cpp:12:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v[nod].size() ; ++i){ ~~^~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:32:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nogcd.in", "r", stdin); ^ main.cpp:33:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nogcd.out", "w", stdout); ^ main.cpp:35:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:39:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^