Several possible approaches

ruby/0153-find-minimum-in-rotated-sorted-array.rb

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+# @param {Integer[]} nums
+# @return {Integer}a
+
+#shortest solution O(n)?
+def find_min(nums)
+ nums.min
+end
+
+#non binary-search iterative approach O(n)
+def find_min(nums)
+ last_num = nums.last
+ nums.each.with_index do |num, i|
+ return num if num <= last_num
+ end
+end
+
+#using ruby's built-in binary search O(log n)
+def find_min(nums)
+ nums.bsearch {|num| num <= nums.last }
+end
+
+#custom binary-search O(log n)
+def find_min(nums)
+ result = nums[0]
+ left = 0
+ right = nums.length - 1
+
+ while left <= right do
+ if nums[left] < nums[right]
+ return [result, nums[left]].min
+ end
+
+ mid = (left + right) / 2
+ result = [result, nums[mid]].min
+
+ if nums[mid] >= nums[left]
+ left = mid + 1
+ else
+ right = mid - 1
+ end
+ end
+
+ return result
+end