1 #include<stdio.h>
 2 const static int NUM = 47;
 3
 4 int quick_sort(int *a, int start, int end){
 5     if (start >= end)
 6         return 0;
 7
 8     int partition = a[start];   //分割点value, 设置为第一个点.最后patition点设置为这个点
 9     int i  = start; //开始点
10     int j  = end;   //结束点
11
12     while(i<j){ //循环多处判断i<j, 结束时i=j
13         while(i<j && a[j] >= partition) //i可置换
14             --j;
15         a[i] = a[j];
16
17         while(i<j && a[i] <= partition) //j可置换
18             ++i;
19         a[j] = a[i];
20     }
21     printf("i=%d j=%d\n", i, j);
22
23     a[i] = partition;   //以上循环结束, i==j, i处即为分割点
24     quick_sort(a, start, i-1);
25     quick_sort(a, i+1, end);
26     return 0;
27 }
28
29 void print(int *a, int start, int end){
30     for (int i = start; i <= end; ++i){
31         printf("%d ", a[i]);
32     }
33     printf("\n");
34 }
35
36 int main(){
37     int a[NUM];
38     for (int i=0;i<NUM;++i){
39         a[i] = i%10;
40     }
41
42     print(a, 0, NUM-1);
43     quick_sort(a, 0, NUM-1);
44     print(a, 0, NUM-1);
45     return 0;
46 }

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 const static int BUCKET = 4;
 4
 5 void print(int *a, int start, int end){
 6     for (int i = start; i <= end; ++i){
 7         printf("%d ", a[i]);
 8     }
 9     printf("\n");
10 }
11
12 int comp(const void *a, const void *b){
13     int va = *(int*)a;
14     int vb = *(int*)b;
15
16     if (va%BUCKET > vb%BUCKET){
17         return 1;
18     }
19     else if (va%BUCKET < vb%BUCKET){
20         return -1;
21     }
22     return va - vb;
23 }
24
25 int main(){
26     int a[] = {3,1,9,5,4,6,2};
27     int NUM = sizeof(a)/sizeof(int);
28
29     print(a, 0, NUM-1);
30     qsort(a, NUM, sizeof(int), comp);
31     print(a, 0, NUM-1);
32     return 0;
33 }