Compilare: main.cpp: In function 'int dfs(int, int)': main.cpp:25:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < T[u].size() ; i ++) ~~^~~~~~~~~~~~~ main.cpp:33:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = 0 ; k < G[j].size() ; k ++) ~~^~~~~~~~~~~~~ main.cpp:39:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:42:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("treegcd.in" , "r" , stdin); ^ main.cpp:43:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("treegcd.out" , "w" , stdout); ^ main.cpp:46:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &n , &m); ^ main.cpp:49:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &x , &y); ^