重温经典之排序 java实现

重新写一遍，都忘记了！

No.1  快排

 1 public class FastSort {
 2     public static void main(String[] args)throws Exception{
 3         int[] a = {10, 1, 2, 3, 7, 3, 8, 5, 6, 4};
 4         FastSort b1 = new FastSort();
 5         b1.sort(a,0,a.length-1);
 6     }
 7     void sort(int[] a ,int l ,int r)throws Exception{
 8         int i,j,t,temp;
 9         i = l ;
10         j = r ;
11         temp = a[l];
12         if(l>r){
13             return;
14         }
15         while (i!=j){
16             while(i<j && a[j]>=temp){
17                 j--;
18             }
19             while(i<j && a[i]<=temp){
20                 i++;
21             }
22             if(i<j){
23                 t = a[i];
24                 a[i] = a[j];
25                 a[j] = t ;
26             }
27         }
28         a[l] = a[i];
29         a[i] = temp;
30         System.out.print("/");
31         for(int h=0;h<a.length;h++){
32             System.out.print(a[h]+" ");
33         }
34         sort(a , l , i-1);
35         sort(a , i+1 , r);
36     }
37 }

No.2 冒泡排序

 1 public class Bubblesort {
 2     public static void main(String []args){
 3         int []a = {3,5,72,3,8,90};
 4         sort(a);
 5     }
 6     public static void sort(int []a){
 7         int temp ;
 8         for(int i = a.length -1 ; i > 0 ; i--){
 9             for(int j = 0 ; j < i ; j++){
10                 if(a[j+1] < a[j]){
11                     temp = a[j+1];
12                     a[j+1] = a[j];
13                     a[j] = temp;
14                 }
15             }
16         }
17         for(int k = 0 ;k<a.length;k++){
18             System.out.print(a[k]+",");
19         }
20     }
21 }

No.3 插入排序

 1 public class Insertsort {
 2     public static void main(String[] args){
 3         int []a = {3,4,4,2,5,4,6,3,2};
 4         sort(a);
 5     }
 6     static void sort(int[] a){
 7         for(int i = 1 ; i < a.length ; i++){
 8             for(int j = i ; j > 0 ; j--){
 9                 if(a[j]<a[j-1]){
10                     int temp = a[j];
11                     a[j] = a[j-1];
12                     a[j-1] = temp;
13                 }
14             }
15         }
16         for(int k = 0;k<a.length;k++)
17             System.out.print(a[k]+" ");
18     }
19 }