Compilare: user.cpp: In function ‘void DP()’: user.cpp:53:29: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if ((j + 1) & 2 == 0) ^ user.cpp: In function ‘void read()’: user.cpp:34:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grazing.in", "r", stdin); ^ user.cpp:35:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp: In function ‘void write()’: user.cpp:86:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grazing.out", "w", stdout); ^