153. Find Minimum in Rotated Sorted Array

Medium
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Suppose an array of length n sorted in ascending order is rotated between 1 and n times. For example, the array nums = [0,1,2,4,5,6,7] might become:
  • [4,5,6,7,0,1,2] if it was rotated 4 times.
  • [0,1,2,4,5,6,7] if it was rotated 7 times.
Notice that rotating an array [a[0], a[1], a[2], ..., a[n-1]] 1 time results in the array [a[n-1], a[0], a[1], a[2], ..., a[n-2]].
Given the sorted rotated array nums of unique elements, return the minimum element of this array.
You must write an algorithm that runs in O(log n) time.
Example 1:
Input: nums = [3,4,5,1,2]
Output:
1
Explanation:
The original array was [1,2,3,4,5] rotated 3 times.
Example 2:
Input: nums = [4,5,6,7,0,1,2]
Output:
0
Explanation:
The original array was [0,1,2,4,5,6,7] and it was rotated 4 times.
Example 3:
Input: nums = [11,13,15,17]
Output:
11
Explanation:
The original array was [11,13,15,17] and it was rotated 4 times.
Constraints:
  • n == nums.length
  • 1 <= n <= 5000
  • -5000 <= nums[i] <= 5000
  • All the integers of nums are unique.
  • nums is sorted and rotated between 1 and n times.

解題

Binary Search
func findMin(nums []int) int {
left := 0
right := len(nums) - 1
​
for left < right {
mid := left + (right - left) / 2
​
if nums[mid] > nums[right] {
left = mid + 1
} else {
right = mid
}
}
​
return nums[right]
}