704

Author: TedTran2019

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