1 /*
2 递归二分查找_I
3 迭代二分查找_R
4
5 */
6
7
8 #include "BinarySearch_I_and_R.h"
9 #include <iostream>
10 using namespace std;
11 int BinarySearch_I(int *a,int nLen,int nTarget);
12 int BinarySearch_R(int *a,int nTarget,int left,int right);
13
14 int main()
15 {
16 int nTest=7;
17 const int nLen = 10;
18 int m[nLen] = {1,2,3,4,5,6,7,8,9,10};
19
20 int nRet = BinarySearch_I(m,nLen,nTest);
21 if (-1 == nRet)
22 {
23 cout <<"迭代二分:没找到"<<endl;
24 }
25 else
26 {
27 cout <<"迭代二分:找到了"<<endl;
28 }
29
30
31 nRet = BinarySearch_R(m,nTest,0,nLen-1);
32 if (-1 == nRet)
33 {
34 cout <<"递归二分:没找到"<<endl;
35 }
36 else
37 {
38 cout <<"递归二分:找到了"<<endl;
39 }
40
41
42
43
44 system("pause");
45 return 0;
46 }
47
48
49 //迭代二分
50 int BinarySearch_I(int *a,int nLen,int nTarget)
51 {
52 int left = 0;
53 int right = nLen-1;
54 int mid;
55
56 while(left <= right)
57 {
58 mid = (left + right) / 2;
59 if (nTarget == a[mid])
60 {
61 return mid;
62 }
63 else if (nTarget > a[mid])
64 {
65 left = mid + 1;
66 }
67 else if (nTarget < a[mid])
68 {
69 right = mid - 1;
70 }
71
72 }
73
74 return -1;
75 }
76
77
78 //递归二分
79 int BinarySearch_R(int *a,int nTarget,int left,int right)
80 {
81
82 if (left <= right)
83 {
84 int mid = (left + right)/2;
85 if (nTarget < a[mid])
86 {
87 return BinarySearch_R(a,nTarget,left,mid-1);
88 }
89 else if (nTarget > a[mid])
90 {
91 return BinarySearch_R(a,nTarget,mid+1,right);
92 }
93 else
94 {
95
96 return mid;
97 }
98 }
99
100
101 return -1;
102 }
