Compilare: user.cpp: In function ‘int bf()’: user.cpp:19:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v[x].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:50:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v[n - 1].size(); ++i) { ^ user.cpp:37:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d", &n, &m); ^ user.cpp:40:44: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d %d", &a, &b, &c); ^