Java - 二分法查找（尚学堂第七章数组）

Posted 2021-02-16 kl_1998

import java.util.Arrays;

public class TestBinarySearch {
    public static void main(String[] args) {
        int[] arr = { 30,20,50,10,80,9,7,12,100,40,8};
        Arrays.sort(arr);//排序
        
        System.out.println(Arrays.toString(arr));
        System.out.println(myBinarySearch(arr,10));
        
        
        
    }
    
    public static int myBinarySearch(int[] arr, int value) {
        int low = 0;
        int high =arr.length-1;
        
        while(low <= high) {
            int mid = (low+high)/2;
            
            if(value == arr[mid]) {
                return mid;
            }
            if(value > arr[mid]) {
                low = mid+1;
            }
            if(value < arr[mid]) {
                high = mid-1;
            }
        }
        
        return -1;
    }
    
}