java 實現二分查找算法

    //二分查找算法的實現
    public static int binarySearch(int[] arr,int search) {
        int low=0;
        int high=arr.length-1;
        //找到中間的索引
        int middleIndex=0;
        while (low<high) {
             middleIndex=(low+high+1)/2;
            if (arr[middleIndex]==search) {
                return middleIndex;
            }
            else if(arr[middleIndex]>search) {
                high=middleIndex-1;
            }
            else {
                low=middleIndex+1;
                
            }
            
        }
        
        return middleIndex;
    }

1 調用

int[] arr=new int[] {1,2,3,4,5,6,7,8,9,10};
int index= binarySearch(arr, 8);
System.out.println("查找的值8位於數組中的索引爲："+index);

 

默認傳入的數組是排好序的