1require "spec_helper"
 2
 3def binary_search(items, target)
 4  lo = 1
 5  hi = items.size
 6  while lo <= hi
 7    mid = lo + (hi-lo)/2
 8    if items[mid] == target
 9      return items[mid]
10    elsif items[mid] < target
11      lo = mid + 1
12    else
13      hi = mid - 1
14    end
15  end
16  nil
17end
18
19describe "binary search" do
20  it "should find the number" do
21    items = [0, 5, 13, 19, 22, 41, 55, 68, 72, 81, 98]
22    result = binary_search(items, 55)
23    expect(result).to eq(55)
24  end
25end