704

ruby/704-Binary-Search.rb

@@ -0,0 +1,33 @@
+# Iteraton
+def search(nums, target)
+ return -1 if nums.empty?
+
+ half = nums.length / 2
+ case nums[half] <=> target
+ when 1
+ search(nums[0...half], target)
+ when -1
+ idx = search(nums[half + 1..-1], target)
+ (idx == -1 ? -1 : half + 1 + idx)
+ when 0
+ half
+ end
+end
+
+# Recursion
+def search(nums, target)
+ left = 0
+ right = nums.length - 1
+ while left <= right
+ half = (left + right) / 2
+ case nums[half] <=> target
+ when 1
+ right = half - 1
+ when -1
+ left = half + 1
+ when 0
+ return half
+ end
+ end
+ -1
+end