-
Notifications
You must be signed in to change notification settings - Fork 0
/
halfsearch.cc
57 lines (55 loc) · 1.23 KB
/
halfsearch.cc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
#include<iostream>
class Solution {
public:
// 二分查找
int halfsearch(int target) {
int arr[] = {1,2,3,4,5};
int size = sizeof(arr) / sizeof(arr[0]);
int left = 0, right = size - 1;
int mid = (left + right) / 2;
while (left <= right) {
//std::cout << mid << "\t" << left << "\t" << right << std::endl;
if (target == arr[mid]) {
return mid;
}
if (target > arr[mid]) {
left = mid + 1;
} else {
right = mid - 1;
}
mid = (left + right) / 2;
}
return -1;
}
// 循环有序数组 O(logN) 查找数字
int halfsearch2(int target) {
int arr[] = {4,5,1,2,3};
int size = sizeof(arr) / sizeof(arr[0]);
int left = 0, right = size - 1;
int mid = (left + right) / 2;
while (left <= right) {
//std::cout << mid << "\t" << left << "\t" << right << std::endl;
if (target == arr[mid]) {
return mid;
}
// 右侧
if (target > arr[mid] && arr[left] > target) {
left = mid + 1;
} else {
right = mid - 1;
}
mid = (left + right) / 2;
}
/*
if (mid >= 0 && mid < size && arr[mid] == target) {
return mid;
}
*/
return -1;
}
};
int main(void) {
Solution solution;
std::cout << solution.halfsearch(2) << std::endl;
std::cout << solution.halfsearch2(2) << std::endl;
}