Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:17: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int LCA(int, int)’: user.cpp:51: warning: unused variable ‘a’ user.cpp:51: warning: unused variable ‘b’ user.cpp: In function ‘int main()’: user.cpp:59: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:60: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:62: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:66: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:74: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:77: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result