二分查找

Posted 2022-07-17 zhichun

 

 

二分查找

 

package demo3;

public class BinarySearch 

    public String binarySearch(int[] array,int key)
    
        int left = 0;
        int right = array.length-1;

        while (left<right)
        
            int mid = left +(right-left)/2;

            if(array[mid]<key)
            
                left=mid+1;
            
            else if(array[mid]>key)
            
                right=right-1;
            
            else if(array[mid]==key)
            
                return "yes";
            

        


        return "no";

    

 

 

 

package demo3;

public class TestBinarySearch 
    public static void main(String[] args) 
        int[] array = 2,1,1,2,3,5,6,7,21,12;

        BinarySearch binary = new BinarySearch();

        System.out.println(  binary.binarySearch(array,4));