冒泡排序，快速排序，归并排序，选择排序，插入排序，堆排序

冒泡：

public class BubbleSort {public static void main(String[] orgs){int[] a = {2,1,10,2,8,6,7,20};for(int i = 0 ; i < a.length; i++){for(int j = 1 ; j <= a.length - 1 - i; j++){if(a[j] < a[j - 1]){int temp = a[j];a[j] = a[j-1];a[j - 1] = temp;}}}for(int foo : a){System.out.print(foo + " ");}}}

快速排序：

public class QuickSort {public int partition(int[] array,int start,int end){int pivot = array[start];while(start < end){while(start < end && array[end] > pivot){end --;}if(start < end){array[start] = array[end];}while(start < end && array[start] <= pivot){start ++;}if(start < end){array[end] = array[start];}}array[start] = pivot;return start;}public void quicksort(int[] array,int start,int end){if(array == null || array.length<=1){return;}if(start < end){int p = partition(array, start, end);quicksort(array,start,p - 1);quicksort(array,p + 1,end);}}public static void main(String[] orgs){QuickSort qs = new QuickSort();int[] a = {2,1,10,2,8,6,7,20};qs.quicksort(a, 0, a.length - 1);for(int foo : a){System.out.print(foo + " ");}}}

归并排序：

public class MergeSort {public void merge(int[] array,int[] temp,int start,int mid, int end){int i = start;int j = mid + 1;for(int k= start; k <= end; k++){temp[k] = array[k];}while(i <= mid && j  <= end){if(temp[i]  <= temp[j]){array[start++] = temp[i];i++;}else{array[start++] = temp[j];j++;}}while(i <= mid){array[start++] = temp[i++];}while(j <= end){array[start++] = temp[j++];}}public void mergesort(int[] array,int[] temp,int start,int end){if(array == null || array.length <= 1){return;}if(start < end){int mid = start + (end - start)/2 ;mergesort(array,temp,start,mid);mergesort(array,temp,mid+1,end);merge(array,temp,start,mid,end);}}public static void main(String[] orgs){MergeSort ms = new MergeSort();int[] a = {2,1,10,2,8,6,7,20};int[] temp = new int[a.length];ms.mergesort(a, temp, 0, a.length - 1);for(int foo : a){System.out.print(foo + " ");}}}

堆排序：

public class HeapSort {public void heapify(int[] array,int start,int end){int length = end;int lchild = 2*start + 1;int rchild = 2*start + 2;int min = start;if(lchild < length && array[min] > array[lchild]){min = lchild;}if(rchild < length && array[min] > array[rchild]){min = rchild;}if(start != min){int temp = array[min];array[min] = array[start];array[start] = temp;heapify(array,min,end);}}public int extractMin(int[] array,int length){int ret = Integer.MIN_VALUE;if(array != null && array.length > 0){ret =  array[0];array[0] = array[length];}return ret;}public void swim(int[] array,int length){if(length < array.length){for(int i = length; i > 0;i = i / 2){if(array[i] < array[i/2]){int temp = array[i];array[i] = array[i/2];array[i/2] = temp;}}}}public static void main(String[] orgs){int[] a = {2,1,10,2,8,6,7,20};HeapSort hs = new HeapSort();int length = a.length - 1;hs.heapify(a,0,length);while(length >= 0){System.out.print(hs.extractMin(a,length) + " ");hs.heapify(a,0,--length);}}}

插入排序：

public class InsertSort {public static void main(String[] orgs){int[] a = {2,1,10,2,8,6,7,20};for(int i = 1 ; i < a.length; i++){for(int j = i; j > 0 && (a[j] < a[j - 1]); j--){int temp = a[j];a[j] = a[j-1];a[j-1] = temp;}}for(int foo : a){System.out.print(foo + " ");}}}

选择排序：

public class SelectSort {public static void main(String[] orgs){int[] a = {2,1,10,2,8,6,7,20};int min = 0;for(int i = 0; i < a.length; i++){min = i;for(int j = i + 1;j < a.length; j++){if(a[j] < a[min]){min = j;}}if(i != min){int temp = a[i];a[i] = a[min];a[min] = temp;}}for(int foo : a){System.out.print(foo + " ");}}}