Compilare: main.cpp: In function 'void dfs(int)': main.cpp:16:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0 ; j < G[x].size() ; j ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:27:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.in" , "r" , stdin); ^ main.cpp:28:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.out" , "w" , stdout); ^ main.cpp:30:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &c); ^ main.cpp:33:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &n , &m); ^ main.cpp:36:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld" , &v[i]); ^ main.cpp:41:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &x , &y); ^