Compilare: main.cpp:3:0: warning: ignoring #pragma optimize [-Wunknown-pragmas] #pragma optimize("O3") main.cpp: In function 'VI zoo::merge(VI, VI)': main.cpp:80:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; fi < a.size() || se < b.size() ;) { ~~~^~~~~~~~~~ main.cpp:80:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; fi < a.size() || se < b.size() ;) { ~~~^~~~~~~~~~ main.cpp:81:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (fi != a.size() && a[fi] < b[se] || se == b.size()) { ~~~^~~~~~~~~~~ main.cpp:81:59: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (fi != a.size() && a[fi] < b[se] || se == b.size()) { ~~~^~~~~~~~~~~ main.cpp:81:36: warning: suggest parentheses around '&&' within '||' [-Wparentheses] if (fi != a.size() && a[fi] < b[se] || se == b.size()) { main.cpp:84:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] } else if (se != b.size() && a[fi] > b[se] || fi == a.size()) { ~~~^~~~~~~~~~~ main.cpp:84:66: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] } else if (se != b.size() && a[fi] > b[se] || fi == a.size()) { ~~~^~~~~~~~~~~ main.cpp:84:43: warning: suggest parentheses around '&&' within '||' [-Wparentheses] } else if (se != b.size() && a[fi] > b[se] || fi == a.size()) { main.cpp: In constructor 'InputReader::InputReader(const char*)': main.cpp:43:52: 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:71:60: 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); ^