81.Search-in-Rotated-Sorted-Array-II.md

81. Search in Rotated Sorted Array II

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题目地址

https://leetcode.com/problems/search-in-rotated-sorted-array-ii/

题目描述

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.

(i.e., [0,0,1,2,2,5,6] might become [2,5,6,0,0,1,2]).

You are given a target value to search. If found in the array return true, otherwise return false.

Example 1:

Input: nums = [2,5,6,0,0,1,2], target = 0
Output: true
Example 2:

Input: nums = [2,5,6,0,0,1,2], target = 3
Output: false
Follow up:

This is a follow up problem to Search in Rotated Sorted Array, where nums may contain duplicates.
Would this affect the run-time complexity? How and why?

代码

Approach #1

https://segmentfault.com/a/1190000016825704

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