[leetcode] Find Minimum in Rotated Sorted Array II

原创于 2015-10-05 21:35:58 发布 · 357 阅读

CC 4.0 BY-SA版权

本文探讨在已排序数组被旋转且可能包含重复元素的情况下，如何找到最小元素，并分析解决方案的时间复杂度优化。通过引入特殊的搜索策略，本文提出一种改进算法来高效解决这一问题。

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

Follow up for "Find Minimum in Rotated Sorted Array":
What if duplicates are allowed?

Would this affect the run-time complexity? How and why?

Suppose a sorted array 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).

Find the minimum element.

The array may contain duplicates.

public class Solution {
    public int findMin(int[] nums) {
        if (nums == null) {
			return 0;
		}
		int l = 0, r = nums.length - 1;
		int ans = nums[0];
		while (l <= r) {
			if (l!=r && nums[l] == nums[r]) {
				++l;
				continue;
			}
			if (nums[l] < nums[r]) {
				return ans < nums[l] ? ans : nums[l];
			}
			int m = (l + r) >> 1;
			if (nums[m] < ans) {
				ans = nums[m];
			}
			if (nums[m] >= nums[l]) {
				l = m + 1;
			} else {
				r = m - 1;
			}
		}
		return ans;
    }
}