Compilare: user.cpp: In function ‘int main()’: user.cpp:25:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0;k<L[j].size();k++){ ^ user.cpp:35:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<L[0].size();i++){ ^ user.cpp:11:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&n,&m); ^ user.cpp:13:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d%d",&a,&b,&c); ^