Introduction to algorithms eighth __ implementing counting sort

Count sort: You don't have to compare the order of sorts, for example. Count sort, cardinal sort, bucket sort in this chapter

Sort By comparison: the order in which the sorting is to be performed. For example, heap ordering in this chapter, high-speed sorting (essentially insert sort), insert sort

Code Listing: Count sort __ Perfect deduction of subscript function

public class Count_sort {//Receive ordered array private int[] a;//sorted array private int[] b;//array for count private int[] c;//initialize public count_s ORT (int[] A) {this. A = A; B = new Int[a.length]; C = new Int[innittemp ()];} Initializes the size of the temporary array public int innittemp () {int bigest = a[0];for (int i = 1; i < a.length; i++) {if (A[i] > bigest) {biges t = A[i];}} return bigest+1;} The count sorts public void sort () {//maps the corresponding element in I to C for (int i = 0; i < a.length; i++) {int value = A[i]; C[value] = C[value] + 1;//use C to count the number of}show (c);//To replace the value meaning of C. How many numbers are smaller than the current subscript for (int i = 1; i < c.length; i++) {C[i] + + c[i-1];} Show (C);//finally come to a[i] element the correct insertion position for (int i = a.length-1; I >= 0; i--) {int value = a[i];//Why 1? Think, assuming that the number is 2 than 5, that 5 should be found in the array of 2 positions, then the 2nd position, corresponding to A[c[value]-1]b[c[value] 1] = value;//This is very important! For example, a[5]==a[2] Such a situation, a[5] inserted the correct position, then a[2] Insert the order of how to calculate it? Just let it follow the a[5]!
C[value]-= 1;} Show (B);} public void Show (int[] X) {for (int i = 0; i < x.length; i++) {int j = x[i]; System.out.print (j + "");} System.out.println (); System.out.println ("--------------------------------------------------------------");} public static void Main (string[] args) {int []a={1,2,3,3,2,1,1,5,1,3,4,5}; Count_sort sort=new Count_sort (A); Sort.sort ();}}

Results of the output:

0 4 2 3 1 2
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0 4 6 9 10 12
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1 1 1 1 2 2 3 3 3 4 5 5
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Introduction to algorithms eighth __ implementing counting sort