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  1. import java.util.*;
  2. import java.lang.*;
  3. import java.io.*;
  4.  
  5. class Ideone
  6. {
  7. 	public static void main (String[] args) throws java.lang.Exception
  8. 	{
  9. 		int start = 1;
  10. 		int end = 65536;
  11.  
  12. 		int[] sieve = getDivisorCount(start, end);
  13. 		long sum = 0;
  14. 		for(int i=0;i<sieve.length;i++){
  15. 			sum += sieve[i];
  16. 		}
  17. 		System.out.println("divisor count: " + sum);
  18. 	}
  19.  
  20. 	public static int[] getDivisorCount(int a, int b){
  21. 		int[] sieve = new int[b - a + 1];
  22. 		double max = Math.ceil(Math.sqrt(b));
  23. 		for(int i = 1; i <= max; i++){
  24. 			int j = (a / i) * i;
  25. 			if(j < a)
  26. 				j += i;
  27. 			for( ; j <= b; j += i){
  28. 				double root = Math.sqrt(j);
  29. 				if(i < root){
  30. 				    sieve[j - a] += 2;
  31. 				}else if(i == root){
  32. 				    sieve[j - a]++;
  33. 				}
  34. 			}
  35. 		}
  36. 		return sieve;
  37. 	}
  38. }
Success #stdin #stdout 0.09s 380224KB
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stdin
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Standard input is empty
stdout
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divisor count: 736974
https://ideone.com/FxvYDZ
http://stackoverflow.com/q/19381617/752320
language:
Java (HotSpot 12)
created:
11 years ago
visibility:
public

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