java JAVA 8中的二进制搜索算法（仅限整数）实现

Posted 2021-05-08

//Xralier 
import java.util.Scanner;

public class BinarySearch {
    
    public static int binarySearch (int ar[] , int key)
    {  
      int low = 0;
      int high = ar.length - 1;
      
        while ( low <= high ) 
          {
           int mid = (low + high) / 2;
           if  ( ar [mid] > key )
                { high = mid - 1; }
          else if ( ar [mid] < key )
                    { low = mid + 1; }
          else
                  return mid;
        }
  return -1 ; 
}
    

    public static void main(String[] args) {
        Scanner in  = new Scanner (System.in);
        System.out.println("Enter Maximum array elements : ");
        int n = in.nextInt();
        int ar [] = new int[n];
        
        System.out.println("Enter array elements : ");
        for (int i = 0 ; i < n ; i++) 
        {
          ar[i]= in.nextInt();
        }
       System.out.println("Enter Key Value to Search : ");
       int k = in.nextInt();
       
       int res = binarySearch(ar,k);
         if   (res>=0)
              {
              System.out.println("Value found at index : " + res);
              }
          if   (res<0)
              {
              System.out.println("Value not found ");
            }
      }
}