个人记录-LeetCode 81. Search in Rotated Sorted Array II

问题：
Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.
(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).

Write a function to determine if a given target is in the array.

The array may contain duplicates.

代码示例：
1、上神器

public class Solution {    public boolean search(int[] nums, int target) {        Set<Integer> set = new HashSet<>();        for (int i : nums) {            set.add(i);        }        return set.contains(target);    }}

2、分段讨论
将原来升序数组的后一部分，移动到了前面，可按下列方式二分法处理：

public class Solution {    public boolean search(int[] nums, int target) {        int start = 0, end = nums.length - 1, mid = -1;        while(start <= end) {            mid = (start + end) / 2;            if (nums[mid] == target) {                return true;            }            //右边是排序的或左侧是未排序的            if (nums[mid] < nums[end] || nums[mid] < nums[start]) {                if (target > nums[mid] && target <= nums[end]) {                    start = mid + 1;                } else {                    end = mid - 1;                }                //左边是排序的或右侧是未排序的            } else if (nums[mid] > nums[start] || nums[mid] > nums[end]) {                if (target < nums[mid] && target >= nums[start]) {                    end = mid - 1;                } else {                    start = mid + 1;                }                //重复部分，++start或--end均可            } else {                end--;            }        }        return false;    }}