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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10.  
  11. public static boolean isPowerOfFour(int num) {
  12. if ((num & (num-1)) != 0) {
  13. return false;
  14. }
  15. int count = 0;
  16. while (num != 1) {
  17. num >>= 1;
  18. count++;
  19. }
  20. return count % 2 == 0;
  21. }
  22.  
  23. public static void main (String[] args) throws java.lang.Exception
  24. {
  25. for (int i = 0 ; i != 20 ; i++) {
  26. System.out.println(i+" "+(1<<i)+ " " +isPowerOfFour(1<<i));
  27. }
  28. }
  29. }
Success #stdin #stdout 0.1s 320512KB
stdin
Standard input is empty
stdout
0 1 true
1 2 false
2 4 true
3 8 false
4 16 true
5 32 false
6 64 true
7 128 false
8 256 true
9 512 false
10 1024 true
11 2048 false
12 4096 true
13 8192 false
14 16384 true
15 32768 false
16 65536 true
17 131072 false
18 262144 true
19 524288 false