Compilare: user.cpp: In function ‘void dfs(const int&)’: user.cpp:57:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < L[node].size(); i ++) ^ user.cpp: In function ‘int main()’: user.cpp:120:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < H[i].size(); j ++) ^ user.cpp:69:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("piese3.in", "r", stdin); ^