Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:23:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < g[act].size() ; ++i) ^ user.cpp: In function ‘int readint()’: user.cpp:40:46: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer , 1 , bsize , stdin); ^ user.cpp:51:46: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer , 1 , bsize , stdin); ^ user.cpp: In function ‘int main()’: user.cpp:60:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbvalmax.in" , "r" , stdin); ^ user.cpp:61:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbvalmax.out" , "w" , stdout); ^ user.cpp:63:34: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer , 1 , bsize , stdin); ^