Compilare: user.cpp: In function ‘int main()’: user.cpp:30:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int it = 0; it < vals.size(); it++) { ~~~^~~~~~~~~~~~~ user.cpp:15:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&n); ^ user.cpp:17:58: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&arr[i].first,&arr[i].second); ^ user.cpp:36:24: warning: ‘id’ may be used uninitialized in this function [-Wmaybe-uninitialized] vals[id] = max(vals[id], arr[p].second); ^