Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:20:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[node].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:50:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lca.in","r",stdin); ^ user.cpp:51:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lca.out","w",stdout); ^ user.cpp:53:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:57:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &dad); ^ user.cpp:65:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &node1, &node2); int left = ap[node1]; int right = ap[node2]; int ind = Log[right-left+1]; ^