Compilare: user.cpp: In function ‘void updateStk(std::vector<int>*, int, int)’: user.cpp:58:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (where >= stk -> size()) { ^ user.cpp:60:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (stk -> size() > ans) ^ user.cpp: In function ‘std::vector<int>* uniteLis(std::vector<int>*, std::vector<int>*)’: user.cpp:115:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < lisStk1 -> size(); ++ i) ^ user.cpp:122:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < lisStk2 -> size(); ++ i) ^ user.cpp: In function ‘std::vector<int>* uniteLds(std::vector<int>*, std::vector<int>*)’: user.cpp:132:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ldsStk1 -> size(); ++ i) ^ user.cpp:139:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ldsStk2 -> size(); ++ i) ^ user.cpp: In function ‘void dfs(int, int)’: user.cpp:171:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < graph[node].size(); ++ i) { ^ user.cpp:179:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < lis1 -> size(); ++ i) { ^ user.cpp:185:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < lds2 -> size(); ++ i) { ^ user.cpp:192:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < lis2 -> size(); ++ i) { ^ user.cpp:198:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < lds1 -> size(); ++ i) { ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:15:47: 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); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:42:51: 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); ^