Compilare: user.cpp: In function ‘void link(const std::vector<int>&, const std::vector<int>&)’: user.cpp:104:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < c0.size(); ++ i) { ^ user.cpp:105:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < c1.size() && intervs[c1[j]].y1 <= intervs[c0[i]].y1) { ^ user.cpp:111:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j < c1.size()) ^ user.cpp: In function ‘void test()’: user.cpp:130:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < all_x.size(); ++ i) ^ user.cpp:137:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= all_x.size() - 2; ++ i) { ^ user.cpp:144:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j < stones[i].size(); ++ j) ^ user.cpp:159:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i <= all_x.size() - 2; ++ i) ^ user.cpp:167:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < intervs.size(); ++ i) ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:36:47: 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 constructor ‘InputReader::InputReader(const char*)’: user.cpp:14:43: 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); ^