Algorithm (algorithms) version 4th Practice 2.2.11 (3)

Key code implementations:

 Public Static voidsort (comparable[] input) {intN =input.length; Aux= Input.clone ();//must be clone (the same as input)//stdout.println ("Input:" + input + "aux:" + aux);//For TestSort (aux, input, 0, N-1); }        //Take input from source, sort it and put output in destination//source and destination are the same at the beginning    Private Static voidSort (comparable[] source, comparable[] destination,intLointhi) {                if(Lo >= hi)//just one entry in array            return; intMid = lo + (Hi-lo)/2; Sort (destination, source, Lo, mid);//First get input from destination, sort it and put output in sourceSort (destination, source, mid+1, HI); Merge (source, Destination, lo, Mid, hi);//merge sorted source to destination            }        Private Static voidMerge (comparable[] source, comparable[] destination,intLointMidinthi) {                inti =Lo; intj = Mid + 1;  for(intK = lo; K <= Hi; k++) {            if(I >mid) Destination[k]= source[j++]; Else if(J >hi) destination[k]= source[i++]; Else if(Less (Source[j], source[i])) Destination[k]= source[j++]; ElseDestination[k]= source[i++]; }//stdout.println ("Source:" + source + "Destination:" + destination);//stdout.printf ("merge (source, destination,%4d,%4d,%4d)", Lo, Mid, hi);//Show (destination);//For Test            }

Test Case:

 PackageCom.qiusongde;Importedu.princeton.cs.algs4.In;ImportEdu.princeton.cs.algs4.StdOut; Public classmergeavoidcopy {Private Staticcomparable[] aux;  Public Static voidsort (comparable[] input) {intN =input.length; Aux= Input.clone ();//must be clone (the same as input)//stdout.println ("Input:" + input + "aux:" + aux);//For TestSort (aux, input, 0, N-1); }        //Take input from source, sort it and put output in destination//source and destination are the same in start    Private Static voidSort (comparable[] source, comparable[] destination,intLointhi) {                if(Lo >= hi)//just one entry in array            return; intMid = lo + (Hi-lo)/2; Sort (destination, source, Lo, mid);//First get input from destination, sort it and put output in sourceSort (destination, source, mid+1, HI); Merge (source, Destination, lo, Mid, hi);//merge sorted source to destination            }        Private Static voidMerge (comparable[] source, comparable[] destination,intLointMidinthi) {                inti =Lo; intj = Mid + 1;  for(intK = lo; K <= Hi; k++) {            if(I >mid) Destination[k]= source[j++]; Else if(J >hi) destination[k]= source[i++]; Else if(Less (Source[j], source[i])) Destination[k]= source[j++]; ElseDestination[k]= source[i++]; }//stdout.println ("Source:" + source + "Destination:" + destination);//stdout.printf ("merge (source, destination,%4d,%4d,%4d)", Lo, Mid, hi);//Show (destination);//For Test            }        Private Static BooleanLess (comparable V, comparable W) {returnV.compareto (W) < 0; }        Private Static voidShow (comparable[] a) {//print the array, on a single line.         for(inti = 0; i < a.length; i++) {stdout.print (A[i]+ " ");            } stdout.println (); }         Public Static Booleanissorted (comparable[] a) { for(inti = 1; i < a.length; i++) {            if(Less (A[i], a[i-1]))                return false; }                return true; }         Public Static voidMain (string[] args) {//Read strings from standard input, sort them, and print.string[] Input =in.readstrings ();//Show (input);//For Testsort (input); assertissorted (input);//Show (input);//For Test            }}

Test results:

m e r G E S O r T e X A m P L e input:[ljava.lang.string;@1b6d3586 Aux:[ljava.lang.string;@4554617csource:[ljava.lang. string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (source, destination,0, 0, 1) e M r G e S O r T E X A M P L e source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,2, 2, 3) e M G r e S O r T E X A M P L e source:[ljava.lang.string;@4554617c destination:[ljava.lang.string;@1b6d3586merge (sou RCE, Destination,0, 1, 3) e G M r e S O r T E X A M P L e source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,4, 4, 5) e M G r e S O r T E X A M P L e source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,6, 6, 7) e M G r e S O r T E X A M P L e source:[ljava.lang.string;@4554617c destination:[ljava.lang.string;@1b6d3586merge (sou RCE, Destination,4, 5, 7) e G M r e O r S T e X A M P L e source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,0, 3, 7) e e G M O r r S T e X A M P L e source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,8, 8, 9) e e G M O r r S E T X A M P L e source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,10, 10, 11) e e G M O r r S E T A X M P L e source:[ljava.lang.string;@4554617c destination:[ljava.lang.string;@1b6d3586merge (sou RCE, Destination,8, 9, 11) e G M r e O r S A e T X M P L e source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,12, 12, 13) e e G M O r r S E T A X M P L e source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,14, 14, 15) e e G M O r r S E T A X M P E L source:[ljava.lang.string;@4554617c destination:[ljava.lang.string;@1b6d3586merge (sou RCE, Destination,12, 13, 15) e G m r e O r S A E T X E L M P source:[ljava.lang.string;@1b6d3586 destination:[ljava.lang.string;@4554617cmerge (sou RCE, Destination,8, 11, 15) e e G m O r r S A e e L M P T X source:[ljava.lang.string;@4554617c destination:[ljava.lang.string;@1b6d3586merge (sou RCE, Destination,0, 7, 15) A e e e g l m m O p r r S T x A e e e g L m m O p r r S t x

Performance comparison:

For 20000random doubles 3333 3.0s

Algorithm (algorithms) version 4th Practice 2.2.11 (3)