Compilare: main.cpp: In function 'void dfs(int)': main.cpp:19:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a[k].size();i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:51:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<c[1].b.size();j++) ~^~~~~~~~~~~~~~ main.cpp:69:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<c[i].b.size();j++) ~^~~~~~~~~~~~~~ main.cpp:32:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("conexidad.in","r",stdin); ^ main.cpp:33:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("conexidad.out","w",stdout); ^ main.cpp:34:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ main.cpp:37:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&i,&j); ^