Problem Link: https://uva.onlinejudge.org/external/118/11879.pdf
Algorithm: This problem is quite easy. In this, there will be a number which is greater at most 100 digits. So, Its not possible to store it in “long long int” in c++.
For a number N, first have to calculate N-1+divisors(N-1) & store it in array (e.g. arr[i]=arr[i-1]+divisors(arr[i-1])).
Make a sequence from 1 to until arr[i] becomes greater than 1000000. Then you will be given two numbers A & B, and you will have to find the number of integers from the above sequence which lies within the range [A,B].
Hints = No critical case. Easy problem.