Compilare: user.cpp: In function ‘void BuildTree()’: user.cpp:100: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void Solve()’: user.cpp:119: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void Read()’: user.cpp:138: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result