Compilare: user.cpp: In function ‘int main()’: user.cpp:22:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < l[r].size(); j++) ^ user.cpp:34:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < l[r].size(); j++) ^ user.cpp:46:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < l[r].size(); j++) ^ user.cpp:15:23: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d ",&n); ^ user.cpp:18:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&o,&x); ^