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]).
Find the minimum element.
You may assume no duplicate exists in the array.
Example 1:
Input: [3,4,5,1,2] Output: 1
Example 2:
Input: [4,5,6,7,0,1,2] Output: 0
难度:medium
题目:假设一个按升序排序的数组在某个未知的轴上旋转。假定数组中没有重复元素。
思路:分情况二叉搜索
Runtime: 0 ms, faster than 100.00% of Java online submissions for Find Minimum in Rotated Sorted Array.
Memory Usage: 37.6 MB, less than 100.00% of Java online submissions for Find Minimum in Rotated Sorted Array.
class Solution { public int findMin(int[] nums) { return findMin(nums, 0, nums.length - 1); } public int findMin(int[] nums, int left, int right) { int mid = left + (right - left) / 2; // 升序 if (nums[left] <= nums[mid] && nums[mid] <= nums[right]) { return nums[left]; } // 降序 if (nums[left] >= nums[mid] && nums[mid] >= nums[right]) { return nums[right]; } // 升序占大降序占小 if (nums[left] >= nums[mid]) { return findMin(nums, left, mid); } // 升序占小降序占大 return findMin(nums, mid, right); } }