Compilare: user.cpp: In function ‘void output()’: user.cpp:26:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (auto i = 0; i < res.size(); ++i) ^ user.cpp: In function ‘bool isSubchain()’: user.cpp:33:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < v.size() && j < b.size()) { ^ user.cpp:33:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < v.size() && j < b.size()) { ^ user.cpp:45:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return i == v.size(); ^ user.cpp: In function ‘void bkt(int)’: user.cpp:49:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (level == a.size()) { ^ user.cpp: In function ‘void input()’: user.cpp:12:39: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d", &lena, &lenb); ^ user.cpp:16:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &el); ^ user.cpp:20:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &el); ^