二分搜索 

 1 #include <iostream>
 2 #include <vector>
 3 #include <string>
 4 
 5 using namespace std;
 6 
 7 //二分搜索
 8 
 9 int binarySearch(int a[],int length,int data) {
10     int left = 0;
11     int right = length - 1;
12 
13     int index = -1;
14     while (left <= right)
15     {
16         int mid = (left + right) / 2;
17         if(a[mid] > data) {
18             right = mid - 1;
19         } else if(a[mid] < data) {
20             left = mid + 1;
21         } else {
22             index = mid;
23             break;
24         }
25     }
26     
27     return index;
28 }
29 
30 int main() {
31     int a[] = {1,2,3,4,5};
32     int index = binarySearch(a,5,3);
33 
34     cout<<index<<endl;
35 }

 

posted on 2021-01-08 16:53  wlqsmiling  阅读(50)  评论(0)  编辑  收藏  举报

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