are you saying that x finally contains the number of bits that are set to 1..??
On Tue, Jul 12, 2011 at 1:09 AM, Dave <[email protected]> wrote: > @rShetty: Ask a question. What do you need to know? > > Dave > > On Jul 11, 1:26 pm, rShetty <[email protected]> wrote: > > Some more Explanation of the working would be helpful > > > > Thank You .. > > > > On Jul 11, 11:11 pm, Dave <[email protected]> wrote: > > > > > > > > > Assuming that the integer is 32 bits, this is pretty good: > > > > > x = (x & 0x55555555) + ((x >> 1) & 0x55555555); > > > x = (x & 0x33333333) + ((x >> 2) & 0x33333333); > > > x = (x & 0x0F0F0F0F) + ((x >> 4) & 0x0F0F0F0F); > > > x = (x & 0x00FF00FF) + ((x >> 8) & 0x00FF00FF); > > > x = (x & 0x0000FFFF) + ((x >> 16) & 0x0000FFFF); > > > > > Notice that the hex constants are respectively alternate bits, > > > alternate pairs of bits, alternate groups of four bits, alternate > > > bytes, and the low-order half of the int. > > > > > The first statement determines the number of one-bits in each pair of > > > bits. The second statement adds adjacent pairs of bits to get the > > > number of bits in each group of four bits. Then these are added to get > > > the number of bits in each byte, short int, and finally in the whole > > > int. > > > > > Dave > > > > > On Jul 11, 12:44 pm, rShetty <[email protected]> wrote: > > > > > > What is the most efficient algorithm to count the number of bits in > an > > > > unsigned integer ? > > > > Explain your approach to the problem ?- Hide quoted text - > > > > - Show quoted text - > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
