Compilare: user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:15:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^ user.cpp: In function ‘bool solve(int, int, std::pair<int, int>)’: user.cpp:98:45: warning: ‘n3’ is used uninitialized in this function [-Wuninitialized] int n1, n2, n3, n4; n1 = n2 = n3, n4 = 0; ^