1 //查找算法：
2 // 顺序查找
3 // 二分查找（插值查找，斐波那契查找）
4 // 二叉排序树查找
5 // 哈希表查找
6
7 #include <iostream>
8 using namespace std;
9
10
11 /*顺序查找*/
12 int sequenceSearch(int* arr, int len, int n)
13 {
14 for (int i = 0; i < len; i++)
15 if (arr[i] == n)
16 return i;
17
18 return -1;
19 }
20
21 /*二分查找（非递归版本）*/
22 int binarySearch(int* arr, int len, int n)
23 {
24 int low = 0, high = n - 1, mid;
25 while (low <= high)
26 {
27 mid = (low + high) >> 1;
28 if (arr[mid] == n)
29 return mid;
30 else if (arr[mid] < n)
31 low = mid + 1;
32 else
33 high = mid - 1;
34 }
35
36 return -1;
37 }
38
39 /*二分查找（递归版本）*/
40 int binarySearch0(int* arr, int n, int low, int high)
41 {
42 if (low <= high)
43 {
44 int mid = (low + high) >> 1;
45
46 if (arr[mid] == n)
47 return mid;
48 else if (arr[mid] < n)
49 binarySearch0(arr, n, mid + 1, high);
50 else
51 binarySearch0(arr, n, low, mid - 1);
52 }
53
54 return -1;
55 }
56
57 /*插值查找*/
58 int insertSearch(int* arr, int len, int n)
59 {
60 int low = 0, high = len - 1, mid;
61 while (low <= high)
62 {
63 if (arr[low] == arr[high]) //处理数组中具有相同值的情况
64 if (arr[low] == n)
65 return low;
66 else
67 return -1;
68
69 mid = (int)(1.0*(n - arr[low]) / (arr[high] - arr[low])*(high - low)); //需要转换为double进行计算
70 if (arr[mid] == n)
71 return mid;
72 else if (arr[mid] < n)
73 low = mid + 1;
74 else
75 high = mid - 1;
76 }
77
78 return -1;
79 }
80
81
82
83 int main()
84 {
85 cout << "请输入数组序列和带查找元素\n（格式：序列长度n 元素1 元素2 ... 元素n 带查找元素num）: " << endl;
86 int n, *parr, num;
87 cin >> n;
88 parr = new int[n];
89 for (int i = 0; i < n; i++)
90 cin >> parr[i];
91 cin >> num;
92
93 cout << "\n1 顺序查找； 2 二分查找（非递归）； 3 二分查找（递归）； 4 插值查找；\n";
94 cout << "请选择查找模式：";
95 int selection, index;
96 while (cin >> selection)
97 {
98 switch (selection)
99 {
100 case 1:
101 index = sequenceSearch(parr, n, num);
102 break;
103 case 2:
104 index = binarySearch(parr, n, num);
105 break;
106 case 3:
107 index = binarySearch0(parr, num, 0, n - 1);
108 break;
109 case 4:
110 index = insertSearch(parr, n, num);
111 break;
112 default:
113 break;
114 }
115
116 if (index == -1)
117 cout << "查找失败！" << endl;
118 else
119 cout << "查找成功！位置：" << index + 1 << endl;
120
121 cout << "\n请选择查找模式：";
122 }
123
124 return 0;
125 }
