Compilare: user.cpp: In function ‘int main()’: user.cpp:10: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:11: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:12: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘int solve(int, int, int, int)’: user.cpp:28: warning: control reaches end of non-void function