Several possible approaches

MikeQCarr · MikeQCarr · commit 6be9c099b8d9 · 2023-01-21T13:30:42.000-06:00
diff --git a/ruby/0153-find-minimum-in-rotated-sorted-array.rb b/ruby/0153-find-minimum-in-rotated-sorted-array.rb
@@ -0,0 +1,44 @@
+# @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
