Algorithm (algorithms) version 4th practice 2.2.11 (2)

Key Code:

    Private Static voidSort (comparable[] input,intLointHi) {                if(lo >= Hi)//just one entry in array            return; intMid = lo + (HI-LO)/2;        Sort (input, lo, mid); Sort (input, Mid+1, hi); if(!less (input[mid+1],input[mid]))//input[mid+1] >= input[mid]            return;            Merge (input, lo, mid, hi); }

Overall:

 packagecom.qiusongde;Importedu.princeton.cs.algs4.In;Importedu.princeton.cs.algs4.StdOut; public classMergeskipmerge {Private Staticcomparable[] aux;  public Static voidsort (comparable[] Input) {intN =input.length; Aux=Newcomparable[n]; Sort (input,0, N-1); }        Private Static voidSort (comparable[] input,intLointHi) {                if(lo >= Hi)//just one entry in array            return; intMid = lo + (HI-LO)/2;        Sort (input, lo, mid); Sort (input, Mid+1, hi); if(!less (input[mid+1],input[mid]))//input[mid+1] >= input[mid]            return;            Merge (input, lo, mid, hi); }        Private Static voidMerge (comparable[] input,intLointMidintHi) {                //copy input[lo,hi] to aux[lo,hi]         for(inti = lo; I <= hi; i++) {aux[i]=input[i]; }                inti =lo; intj = Mid + 1;  for(intK = lo; K <= hi; k++) {            if(i >Mid) input[k]= aux[j++]; Else if(j >Hi) input[k]= aux[i++]; Else if(less (aux[j], aux[i])) input[k]= aux[j++]; Elseinput[k]= aux[i++]; } stdout.printf ("merge (input,%4d,%4d,%4d)", lo, mid, hi); Show (input);//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 merge (input,0, 0, 1) e M r G e S O r T E X A M P L e merge (input,2, 2, 3) e M G r e S O r T E X A M P L e merge (input,0, 1, 3) e G M r e S O r T E X A M P L e merge (input,4, 5, 7) e G M r e O r S T e X A M P L e merge (input,0, 3, 7) e e G M O r r S T e X A M P L e merge (input,8, 8, 9) e e G M O r r S E T X A M P L e merge (input,10, 10, 11) e e G M O r r S E T A X M P L e merge (input,8, 9, 11) e e G M O r r S A e T X M P L e merge (input,14, 14, 15) e e G M O r r S A e T X M P E L merge (input,12, 13, 15) e e G M O r r S A e T X E L M P merge (input,8, 11, 15) e e G m O r r S A e e L M P T X merge (input,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 20000 random doubles3.6s mergefasterm are 3.3s Mergeuseinsert are 3.2s mergeskipmerge is 3.4s

Algorithm (algorithms) version 4th practice 2.2.11 (2)