java - 二分查找的比较次数

Question

是否可以计算递归二分查找的比较次数？如果是这样，怎么办？

这是我所指的搜索:

//binary search
public static int binarySearch(int[] items, int start, int end, int goal)
{
    if (start > end)
        return (-1);
    else
    {
        int mid = (start + end)/2;
        if (goal == items[mid])
            return (mid);
        else
        if (goal < items[mid])
            return (binarySearch(items, start, mid - 1, goal));
        else
            return (binarySearch(items, mid + 1, end, goal));
    }
}//end binarySearch

Answer 1

在方法外部声明计数变量。然后每次调用该方法时加 1。

long count = 0;
//binary search
public static int binarySearch(int[] items, int start, int end, int goal)
{
    count += 1
    if (start > end)
        return (-1);
    else
    {
        int mid = (start + end)/2;
        if (goal == items[mid])
            return (mid);
        else
        if (goal < items[mid])
            return (binarySearch(items, start, mid - 1, goal));
        else
            return (binarySearch(items, mid + 1, end, goal));
     }
}//end binarySearch