Old text-bitsort sorting algorithm-2007-10-10 16:08

"Programming Pearls" in the introduction of the algorithm. the complexity of the algorithm is O (x), and X is the maximum number to sort. Not suitable for sorting with duplicate data, the duplicated data is treated as a data output.

Or look at the code!

C Program implementation:
Selected from "Programming Pearls"

/*bitsort.c--bitmap sort from Column 1 * sort distinct integers in the range [0. . N-1]*/#include<stdio.h>#defineBitsperword 32//define each int type to hold 32 bits  #defineSHIFT 5//32=2^5  #defineMASK 0x1F//5-bit masking  #defineN 10000000//bit arrays total number of bits    inta[1+ N/bitsperword];//bit arrays are implemented using an int array.     void   Set(inti) {A[i>>shift] |= (1<< (I & MASK)); }//Place 1 position i           /*extract the first bit of the array because each int holds 32 bits, the integer part of I/32 is the element in the int array, and the remainder part of the displacement Substitution Division I/32 is the corresponding number of bits in the int array.               For example i=61, then I/32 = 1 means i=61 in the a[1] element, i/32 remainder is 29=i&mask, which means that the 29th bit in the a[1] element is saved */  voidclrinti) {A[i>>shift] &= ~ (1<< (I & MASK)); }//Clear 0 The first I bit  intTestinti) {returnA[i>>shift] & (1<< (I & MASK)); }//extract the value of the I-bit     intMain () {inti;  for(i =0;   i < N; i++) CLR (i); //set each bit of the array to 0//because bit-wise operation is not efficient, you can use the following three lines to assign values to an array of integers instead                /*Replace above 2 lines with below 3 for word-parallel init int top = 1 +                  N/bitsperword;   for (i = 0;   i < top;                  i++) A[i] = 0; */                   while(SCANF ("%d", &i)! = EOF)//set the corresponding bit according to the value entered                   Set(i);  for(i =0;   i < N; i++)//detect which one is 1                   if(Test (i)) printf ("%d", i); return   0; }   

Python language implementations:
Excerpt from: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/528942

1 #Python implementation of Bitsort algorithm from "Programming Pearls"2 #http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/5289423 4 defbitsort (filename, MAXN):5     """Sort a file named ' filename ' which6 consists of maxn integers where each7 integer is less than MAXN"""8 9     #Initialize BitmapTenA = [0]*MAXN One  A     #Read from file and fill bitmap -      forLineinchfile (filename): -n =Int (Line.strip ()) the         #Turn bits on for numbers -         ifN<maxn:a[n] = 1 -  -     #Return A generator that iterates over the list +      forNinchRange (len (a)): -         ifA[n]==1:yieldN +  A      at if __name__=="__main__": -     #numbers.txt should contain a list of numbers -     #Each of the than 1000000, one per line. -      forNuminchBitsort ('Numbers.txt', 1000000): -         PrintNum

Old text-bitsort sorting algorithm-2007-10-10 16:08