minuni.cpp: In function 'void preproc()': minuni.cpp:42: warning: unused variable 'k' minuni.cpp: In function 'void read_and_solve()': minuni.cpp:66: warning: unused variable 'j' minuni.cpp:66: warning: unused variable 'k' minuni.cpp:68: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result minuni.cpp:72: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result minuni.cpp: In function 'int main()': minuni.cpp:93: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result minuni.cpp:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result