Search in Rotated Sorted Array

给一个排序后被partial翻转的数组, 找一个元素. 利用排序, 做二叉搜索. 主要是要分类讨论.

public class Solution {
    public int search(int[] nums, int target) {
        if(nums.length == 0 || nums == null)
            return 0;
        int l = 0;
        int r = nums.length - 1;
        while(l <=r) {
            int mid = l + (r - l) / 2;
            if(nums[mid] == target)
                return mid;
            else if(nums[mid] >= nums[l]){
                if(nums[l]<=target && target < nums[mid])
                    r = mid - 1;
                else
                    l = mid + 1;
            }
            else{
                if(nums[mid] < target && target <= nums[r])
                    l = mid + 1;
                else
                    r = mid - 1;
            }
        }
        return -1;
    }
}