33. 搜索旋转排序数组

class Solution {
    public int search(int[] nums, int target) {
         if(nums==null||nums.length==0){
            return -1;
        }
        int start=0;
        int end=nums.length-1;
        while(start<=end){   
            int mid=start+(end-start)/2;
            if(nums[mid]==target){
                return mid;
            }
            if(nums[start]<=nums[mid]){ //判断左侧区间递增
                if(target>=nums[start]&&target<nums[mid]){   //判断是否位于区间之中
                    end=mid-1;
                }else{
                    start=mid+1;
                }
            }else{                       //判断右侧区间递增
                if(target>nums[mid]&&target<=nums[end]){   //判断是否位于这个区间 
                    start=mid+1;
                }else{
                    end=mid-1;
                }
            }
        }
        return -1;
    }
}