Sort algorithm One: Insert sort (insertion sort)

Recently from NetEase Open class in the MIT Open Class "Introduction to the algorithm," The feeling is good, the next few articles shown in the study diary, not ready to do too much to describe the algorithm details, interested can see for themselves.

The article is divided into several classical sorting algorithms, directly on the code, according to the results of the algorithm performance has a visual understanding. This article first says insert sort (insertion sort).

(i) Algorithm implementation

1 protected voidSortint[] tosort) {2         if(Tosort.length <= 1) {3             return;4         }5          for(inti = 1; i < tosort.length; i++) {6             if(Tosort[i] < tosort[i-1]) {7                 intj =i;8                 inttemp =Tosort[i];9                  while(J > 0 && Temp < tosort[j-1]) {TenTOSORT[J] = tosort[j-1]; Onej--; A                 } -TOSORT[J] =temp; -             } the         } -}

Insertion Sort

1) Insert sort is in place sort, save space

2) The time complexity of insertion sequencing is O (n2)

(ii) Algorithmic performance

**************************************************
Number to Sort is:2500
Array to sort is:{665184,192100,475135,171530,869545,506246,640618,543738,91353,493005 ...}
Cost time of "Insertionsort" is (milliseconds): 3
Sort result of "Insertionsort": {856,985,2432,3792,3910,3915,4423,4516,4653,4780 ...}
**************************************************
Number to Sort is:25000
Array to sort is:{99880,631403,265087,597224,876665,955084,996547,879081,197806,926881 ...}
Cost time of "Insertionsort" is (milliseconds): 267
Sort result of "Insertionsort": {14,14,17,83,97,152,179,199,240,299 ...}
**************************************************
Number to Sort is:250000
Array to sort is:{777293,731773,508229,920721,338608,707195,940,445210,19071,768830 ...}
Cost time of "Insertionsort" is (milliseconds): 21,523
Sort result of "Insertionsort": {2,7,7,19,19,21,24,29,30,39 ...}

Related code:

1  PackageCom.cnblogs.riyueshiwang.sort;2 3 Importjava.util.Arrays;4 5  Public classInsertionsortextendsAbstractsort {6 @Override7     protected voidSortint[] tosort) {8         if(Tosort.length <= 1) {9             return;Ten         } One          for(inti = 1; i < tosort.length; i++) { A             if(Tosort[i] < tosort[i-1]) { -                 intj =i; -                 inttemp =Tosort[i]; the                  while(J > 0 && Temp < tosort[j-1]) { -TOSORT[J] = tosort[j-1]; -j--; -                 } +TOSORT[J] =temp; -             } +         } A     } at  -      Public Static voidMain (string[] args) { -          for(intj = 0, n = 2500; J < 3; j + +, n = n * 10) { - System.out -. println ("**************************************************"); -System.out.println ("Number to Sort is:" +n); in             int[] array = Commonutils.getrandomintarray (n, 1000000); -System.out.print ("Array to sort is:"); to Commonutils.printintarray (array); +  -             int[] Array1 =arrays.copyof (array, n); the             NewInsertionsort (). Sortandprint (array1); *         } $     }Panax Notoginseng}

Insertionsort.java

1  PackageCom.cnblogs.riyueshiwang.sort;2 3 ImportJava.text.MessageFormat;4 5  Public Abstract classAbstractsort {6     /**7      * 8      * @paramTosort9 * Array to sortTen      */ One     protected Abstract voidSortint[] tosort); A  -      Public voidSortandprint (int[] tosort) { -Long begin =System.currenttimemillis (); the sort (tosort); -Long end =System.currenttimemillis (); - System.out.println (Messageformat.format ( -"Cost time of" {0} "is (milliseconds): {1}", This. GetClass () +. Getsimplename (), (End-( begin) )); -System.out.print (Messageformat.format ("Sort result of" {0} ":", This + . GetClass (). Getsimplename ())); A Commonutils.printintarray (tosort); at     } -  -}

Abstractsort.java

1  PackageCom.cnblogs.riyueshiwang.sort;2 3 ImportJava.util.Random;4 5  Public classCommonutils {6     Private StaticRandom random =NewRandom ();7 8      Public Static voidPrintintarray (int[] Array) {9System.out.print (' {'));Ten  One         intLength = Math.min (Array.Length, 10); A          for(inti = 0; i < length; i++) { - System.out.print (Array[i]); -             if(I! = length-1) { theSystem.out.print (', '); -}Else { -                 if(Array.Length > 10) { -System.out.print ("..."); +                 } -System.out.println ('} '); +             } A         } at     } -  -      Public Static int[] Getrandomintarray (intSizeintmaxValue) { -         int[] Array =New int[size]; -          for(inti = 0; i < size; i++) { -Array[i] =Random.nextint (maxValue); in         } -         returnArray; to     } +  -      Public Static voidSwapint[] Tosort,intIintj) { the         inttemp =Tosort[i]; *Tosort[i] =Tosort[j]; $TOSORT[J] =temp;Panax Notoginseng     } -}

Commonutils.java

Sort algorithm One: Insert sort (insertion sort)