Java的二分查找

Posted 2021-01-16 白包子

今天学习了二分查找，虽然代码简单，但还是要有必要，记录一下今天的学习的。

 1 public class TestBrinarySeach {
 2     public static void main(String[] args) {
 3         int[] arr = {24,32,15,56,39,44,87,65,59};
 4         Arrays.sort(arr);
 5         
 6         int value = 39;//要查找的值        
 7 
 8         System.out.println(Arrays.toString(arr));
 9         System.out.println(myBrinarySeach(arr, value)+1);       
10      
11     }
12 
13 
14 
15 public static int myBrinarySeach(int[] arr,int value){
16         int low = 0;
17         int high = arr.length-1;
18         
19         while(low<=high){
20             int mid = (low+high)/2;
21             
22             if(value==arr[mid]){
23                 return mid;
24             }
25             if(value>arr[mid]){
26                 low = mid+1;
27             }
28             if(value<arr[mid]){
29                 high = mid-1;
30             }
31         }
32         return -1;
33     }
34 }