Compilare: user.cpp: In function ‘int back(int, long long int)’: user.cpp:66: warning: no return statement in function returning non-void user.cpp: In function ‘int main()’: user.cpp:79: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:80: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:82: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:84: warning: ‘sol’ may be used uninitialized in this function