Comparison tree
Java program
In this program, R1,…,RN were simplified to K1,…,KN.
/**
* Created with IntelliJ IDEA.
* User: 1O1O
* Date: 12/11/13
* Time: 6:52 PM
* :)~
* Shar's Method:Searching
*/
public class Main {
public static void main(String[] args) {
int N = 16;
int[] K = new int[18];
/*Prepare the ordered data table*/
K[1] = 61;
K[2] = 87;
K[3] = 154;
K[4] = 170;
K[5] = 275;
K[6] = 426;
K[7] = 503;
K[8] = 509;
K[9] = 512;
K[10] = 612;
K[11] = 653;
K[12] = 677;
K[13] = 703;
K[14] = 765;
K[15] = 897;
K[16] = 908;
/*Output sorted Ks*/
System.out.println("Sorted Ks:");
for(int i=1; i<=N; i++){
System.out.println(i+":"+K[i]);
}
System.out.println();
/*Kernel of the Algorithm!*/
int Key = 653; /*Key to be found*/
K[0] = -10000; /*Negative Infinite*/
K[17] = 10000; /*Positive Infinite*/
int k = (int)Math.floor(Math.log(N)/Math.log(2));
int i = (int)Math.pow(2, k);
int delta = (int)Math.pow(2, k);
int l = (int)Math.ceil(Math.log(N-Math.pow(2, k)+1)/Math.log(2));
if(Key > K[i]){
delta = (int)Math.pow(2, l);
i = N+1-(int)Math.pow(2, l);
i = i+(int)Math.ceil((double)delta/2);
delta = (int)Math.floor((double)delta/2);
}
do{
if(Key < K[i]){
if(delta == 0){
System.out.println("Outputs: "+Key+" not found.");
break;
}else {
i = i-(int)Math.ceil((double)delta/2);
delta = (int)Math.floor((double)delta/2);
}
}else if(Key > K[i]){
if(delta == 0){
System.out.println("Outputs: "+Key+" not found.");
break;
}else {
i = i+(int)Math.ceil((double)delta/2);
delta = (int)Math.floor((double)delta/2);
}
}else {
System.out.println("Outputs: "+Key+" in K["+i+"].");
break;
}
}while (true);
}
}
Outputs
Sorted Ks:
1:61
2:87
3:154
4:170
5:275
6:426
7:503
8:509
9:512
10:612
11:653
12:677
13:703
14:765
15:897
16:908
Outputs: 653 in K[11].
Reference
<< The art of computer programming: Sorting and Searching >> VOLUME 3, DONALD E. KNUTH