1 #include <stdio.h>
2
3 #define CUTOFF 3
4
5 typedef int ElementType;
6
7 void SwapTwoNum(ElementType *Num_1,ElementType *Num_2)
8 {
9 int NumTemp = *Num_1;
10 *Num_1 = *Num_2;
11 *Num_2 = NumTemp;
12 }
13
14 // Return Median of left,center,and right
15 //order these and hide the pivot
16 ElementType Median3(ElementType *Array,int Left,int Right)
17 {
18 int Center = (Left + Right) / 2;
19
20 // C >= L,R >= L,R >= C ---> L <= C <= R
21 if(Array[Left] > Array[Center])
22 {
23 SwapTwoNum(&Array[Left],&Array[Center]);
24 }
25 if(Array[Left] > Array[Right])
26 {
27 SwapTwoNum(&Array[Left],&Array[Right]);
28 }
29 if(Array[Center] > Array[Right])
30 {
31 SwapTwoNum(&Array[Center],&Array[Right]);
32 }
33
34 //Hide pivot
35 SwapTwoNum(&Array[Center],&Array[Right-1]);
36 return Array[Right-1];
37 }
38
39 void InsertionSort(ElementType *Array,int ArrayLen)
40 {
41 int i,j;
42 ElementType ExtractElem;
43 for(i = 1;i < ArrayLen;i ++)
44 {
45 ExtractElem = Array[i];
46 for(j = i;j > 0 && ExtractElem < Array[j-1];j --)
47 {
48 Array[j] = Array[j-1];
49 }
50 //Insert
51 Array[j] = ExtractElem;
52 }
53 }
54
55 void QSort(ElementType *Array,int Left,int Right)
56 {
57 int i,j;
58 ElementType Pivot;
59
60 if(Left + CUTOFF <= Right)
61 {
62 Pivot = Median3(Array,Left,Right);
63 i = Left;j = Right - 1;
64 while(1)
65 {
66 while(Array[++i] < Pivot)
67 ;
68 while(Array[--j] > Pivot)
69 ;
70 if(i < j)
71 {
72 SwapTwoNum(&Array[i],&Array[j]);
73 }
74 else
75 {
76 break;
77 }
78 }
79
80 //restore pivot
81 SwapTwoNum(&Array[i],&Array[Right-1]);
82
83 QSort(Array,Left,i-1);
84 QSort(Array,i+1,Right);
85 }
86 else
87 {
88 InsertionSort(Array+Left,Right-Left+1);
89 }
90 }
91
92 void QuickSort(ElementType *Array,int ArrayLen)
93 {
94 QSort(Array,0,ArrayLen-1);
95 }
96
97 int main()
98 {
99 ElementType TestArray[10] = {718,224,3332,4443,55,31,66,79,90,7};
100 QuickSort(TestArray,10);
101 int i;
102 for(i = 0;i < 10;i ++)
103 {
104 printf("%d ",TestArray[i]);
105 }
106 printf("\n");
107 return 0;
108 }
