Java Sorting algorithm

Overview:

Here is a demonstration of the various sorting algorithms using Java.

Bubble Sort

public class Bubblesort {public static int[] Bubblesort (int[] array) {if (array = = NULL) {return null;} for (int i = 0, i < array.length; i++) {for (int j = i + 1; j < Array.Length; J + +) {if (Array[i] > Array[j]) {arr Ay[i] = Array[i] + array[j];array[j] = Array[i]-array[j];array[i] = Array[i]-array[j];}}} return array;}}

Insert Sort

public class Insertsort {public static int[] Insertsort (int[] array) {if (array = = NULL) {return null;} for (int i = 1; i < Array.Length; i++) {for (int j = i; (J > 0) && (Array[j] < array[j-1]); j--) {Sortutils.swap (array, J, j-1);}} return array;}}

Select Sort

public class Selectionsort {public static int[] Selectionsort (int[] array) {if (array = = NULL) {return null;} for (int i = 0; i < Array.Length; i++) {int lowindex = i;for (int j = array.length-1; j > i; j--) {if (Array[j] &l T Array[lowindex]) {lowindex = j;}} Sortutils.swap (Array, I, Lowindex);} return array;}}

Shell Sort

public class Shellsort {public static int[] Shellsort (int[] array) {if (array = = NULL) {return null;} for (int i = ARRAY.LENGTH/2; i > 2; I/= 2) {for (int j = 0; J < i; J + +) {Insertsort (array, J, i);}} Insertsort (Array, 0, 1); return array;} private static void Insertsort (int[] array, int start, int Inc) {for (int i = start + inc; I < array.length; i + = Inc) {for (int j = i; (J >= Inc) && (Array[j] < array[j-inc]); J-= Inc) {Sortutils.swap (array, J, J-inc);}}}

Quick Sort

public class Qksort {public static int[] QuickSort (int[] array) {if (array! = NULL) {return QuickSort (array, 0, array.length-1);} return null;} private static int[] QuickSort (int[] array, int beg, int end) {if (Beg >= end | | array = = NULL) {return null;} int p = partition (array, beg, end), QuickSort (array, Beg, p-1), QuickSort (array, p + 1, end); return array;} /** * Find the demarcation point * @param array * @param beg * @param end * @return */private static int partition (int[] array, int beg, int en d) {int last = Array[end];int i = beg-1;for (int j = Beg; J <= End-1; + j) {if (Array[j] <= last) {i++;if (i! = j) {Array[i] = Array[i] ^ array[j];array[j] = Array[i] ^ Array[j];array[i] = Array[i] ^ array[j];}} if ((i + 1) = end) {array[i + 1] = array[i + 1] ^ array[end];array[end] = array[i + 1] ^ Array[end];array[i + 1] = array[ i + 1] ^ array[end];} return i + 1;}} 

Heap Sort

public class Heapsort {public static int[] Heapsort (int[] array) {if (array = = NULL) {return null;} Maxheap h = new Maxheap (), H.init (array), for (int i = 0; i < Array.Length; i++) {H.remove ();} System.arraycopy (H.queue, 1, array, 0, array.length); return array;} private static class Maxheap {void init (int[] data) {This.queue = new Int[data.length + 1];for (int i = 0; i < Data.len Gth i++) {Queue[++size] = data[i];fixup (size);}} private int size = 0;private int[] queue;public int get () {return queue[1];} public void Remove () {Sortutils.swap (queue, 1, size--); Fixdown (1);} fixdownprivate void Fixdown (int k) {int J;while ((j = k << 1) <= size) {if (J < size && Queue[j] &l T Queue[j + 1]) {j + +;} Do not swap if (Queue[k] > Queue[j]) {break;} Sortutils.swap (Queue, J, k); k = j;}} private void fixup (int k) {while (K > 1) {int j = k >> 1;if (Queue[j] > Queue[k]) {break;} Sortutils.swap (Queue, J, k); k = j;}}}

Merge Sort

public class MergeSort {public static int[] MergeSort (int[] array) {if (array = = NULL) {return null;} int[] temp = new Int[array.length];return mergesort (array, temp, 0, array.length-1);} private static int[] MergeSort (int[] array, int[] temp, int l, int r) {int mid = (L + R)/2;if (L = = r) {return null;} MergeSort (Array, temp, L, mid), MergeSort (Array, temp, mid + 1, R), for (int i = l; I <= R; i++) {temp[i] = array[i];} int i1 = L;int I2 = mid + 1;for (int cur = l; cur <= r; cur++) {if (I1 = = Mid + 1) {Array[cur] = temp[i2++];} else if ( I2 > R) {array[cur] = temp[i1++];} else if (Temp[i1] < Temp[i2]) {array[cur] = temp[i1++];} else {array[cur] = temp[ i2++];}} return array;}}

merge sort (improved)

public class Mergesortimproved {private static final int THRESHOLD = 10;public static int[] MergeSort (int[] array) {if (AR Ray = = null) {return null;} int[] temp = new Int[array.length];return mergesort (array, temp, 0, array.length-1);} private static int[] MergeSort (int[] array, int[] temp, int l, int r) {int I, j, k;int mid = (L + R)/2;if (L = = r) {Retu RN null;} if ((mid-l) >= THRESHOLD) {mergesort (array, temp, L, mid),} else {Insertsort (array, L, mid-l + 1);} if ((R-mid) > THRESHOLD) {mergesort (array, temp, mid + 1, r),} else {Insertsort (array, mid + 1, r-mid);} for (i = l; I <= mid; i++) {temp[i] = array[i];} for (j = 1; J <= R-mid; j + +) {temp[r-j + 1] = Array[j + mid];} int a = Temp[l];int B = temp[r];for (i = l, j = r, k = l; k <= R; k++) {if (a < b) {Array[k] = Temp[i++];a = Temp[i] ;} else {Array[k] = Temp[j--];b = Temp[j];}} return array;} private static void Insertsort (int[] array, int start, int len) {for (int i = start + 1; i < start + len; i++) {for (int j = i; (J > Start) && array[j] < array[j-1]; j--) {Sortutils.swap (array, J, j-1);}}}

full Source code download (includes test case and Tool Class):

http://download.csdn.net/detail/u013761665/8698287

Java Sorting algorithm