排序算法Java实现

import java.util.Random;public class Sort {//Bubble sort  时间复杂度为O（n^2）public void bubbleSort(int a[]){int temp = 0;int count = 0;for(int i=0;i<a.length;++i){count = 0;for(int j=0;j<a.length-1;++j){if(a[j]>a[j+1]){temp = a[j];a[j] = a[j+1];a[j+1] = temp;++count;}}System.out.println("i="+i+",count="+count);if(count==0)break;}}//Select Sort  时间复杂度为O（n^2）public void selectSort(int a[]){int min_index= 0;int temp = 0;for(int i=0;i<a.length;++i){min_index = i; for(int j=i+1;j<a.length;++j){if(a[j]<a[min_index])min_index = j;}if(min_index!=i){temp = a[min_index];a[min_index] = a[i];a[i] = temp;}}}//insert sort   时间复杂度为O（n^2）public void insertSort(int a[]){int temp = 0;int j = 0;for(int i=1;i<a.length;++i){if(a[i]<a[i-1]){temp = a[i];j = i-1;do{a[j+1] = a[j];--j;}while(j>=0 && temp<a[j]);a[j+1] = temp;}}}//Shell Sort  public void shellSort(int a[]){int gap = a.length;int j = 0;int temp = 0;do{gap = gap/3+1;for(int i=gap;i<a.length;++i){if(a[i]<a[i-gap]){temp = a[i];j = i-gap;do{a[j+gap] = a[j];j -= gap;}while(j>=0 && temp<a[j]);a[j+gap] = temp;}}}while(gap>1);}//Quick Sort  时间复杂度为O(n*log2 n)void quickSort(int arr[],final int left,final int right){if(left<right){int pivotpos = partition(arr,left,right);quickSort(arr,left,pivotpos-1);quickSort(arr,pivotpos+1,right);}}int partition(int arr[],final int low,final int high){int pivotpos = low;int temp = 0;for(int i=low+1;i<=high;++i){if(arr[low]>arr[i]){++pivotpos;if(pivotpos!=i){temp = arr[i];arr[i] = arr[pivotpos];arr[pivotpos] = temp;}}}temp = arr[low];arr[low] = arr[pivotpos];arr[pivotpos] = temp;return pivotpos;}public static void main(String[]args){final int SIZE = 30;int arr[]=new int[SIZE];Sort sort = new Sort();Random rand = new Random();for(int i=0;i<SIZE;++i){//produce random number,maximum is 100arr[i] = rand.nextInt(100);System.out.print(arr[i]+"  ");}System.out.println();/****************************************************************System.out.println("Bubble Sort:");sort.bubbleSort(arr);for(int i=0;i<arr.length;i++){System.out.print(arr[i]+"  ");}System.out.println();****************************************************************//**************************************************************System.out.println("Select Sort:");sort.selectSort(arr);for(int i=0;i<arr.length;++i)System.out.print(arr[i]+"  ");System.out.println();***************************************************************//**************************************************************System.out.println("Insert Sort:");sort.insertSort(arr);for(int i=0;i<arr.length;++i)System.out.print(arr[i]+"  ");System.out.println();****************************************************************//***************************************************************System.out.println("Shell Sort:");sort.shellSort(arr);for(int i=0;i<arr.length;++i)System.out.print(arr[i]+"  ");System.out.println();*****************************************************************//****************************************************************/System.out.println("Quick Sort:");sort.quickSort(arr, 0, arr.length-1);//int a[] = {21,25,16,8,60,49};//sort.quickSort(a, 0, a.length-1);for(int i=0;i<arr.length;++i)System.out.print(arr[i]+"  ");System.out.println();}}

更多排序算法有个博客链接排序算法总结！