Compilare: user.cpp: In function ‘int main()’: user.cpp:43:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[v[a][0]].size();++i)if(v[v[a][0]][i]==a)v[v[a][0]].erase(v[v[a][0]].begin()+i); ^ user.cpp:23:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi, "%hd %hd", &n, &k); ^ user.cpp:26:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi, "%hd %hd", &a, &b); ^