Compilare: main.cpp: In lambda function: main.cpp:63:20: warning: suggest parentheses around '&&' within '||' [-Wparentheses] if (!r && graph[node][cyc[i]] || r && graph[cyc[i]][node]) { ~~~^~~~~~~~~~~~~~~~~~~~~~ main.cpp: In constructor 'InputReader::InputReader(const char*)': main.cpp:11:43: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ main.cpp: In member function 'void InputReader::advance()': main.cpp:33:47: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^