Compilare: main.cpp: In constructor 'DSU::DSU(int)': main.cpp:40:21: warning: 'DSU::sz' will be initialized after [-Wreorder] vector<int> link, sz, cost; ^~ main.cpp:40:15: warning: 'std::vector<int> DSU::link' [-Wreorder] vector<int> link, sz, cost; ^~~~ main.cpp:42:3: warning: when initialized here [-Wreorder] DSU(int n) : n(n), sz(n, 1), link(n, -1), cost(n, -1) {} ^~~ main.cpp: In constructor 'InputReader::InputReader(const char*)': main.cpp:11:41: 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:33:43: 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); ^