Compilare: user.cpp: In function ‘int main()’: user.cpp:55:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < vec[a].size(); i++) { ^ user.cpp:39:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d", &n, &m); ^ user.cpp:42:41: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d%d", &a, &b, &c); ^