Compilare: main.cpp: In function 'void DFS2(int, int, int)': main.cpp:99:41: warning: variable 'son2' set but not used [-Wunused-but-set-variable] int down1 = 0, son1 = 0, down2 = 0, son2 = 0; ^~~~ main.cpp: In constructor 'InputReader::InputReader(const char*)': main.cpp:25:43: 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:70:47: 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); ^ main.cpp: In function 'int main()': main.cpp:148:21: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized] DFS2(root, 0, 1); ^