Compilare: user.cpp: In function ‘void open_files()’: user.cpp:14: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:15: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void read()’: user.cpp:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘int search(unsigned int)’: user.cpp:55: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int solve_subseq(int)’: user.cpp:63: warning: comparison between signed and unsigned integer expressions