Trying to fix a bug and questioning my sanity, until I found this..
import algorithm
echo binarySearch([8, 2, 5, 4], 5) # 2
echo binarySearch([8, 2, 5, 4, 7], 5) # 2
echo binarySearch([8, 2, 5, 4, 7, 0], 5) # -1
echo binarySearch([8, 2, 5, 4, 7, 0, 1], 5) # -1
echo binarySearch([8, 2, 5, 4, 7, 0, 1, 6], 5) # 2
echo binarySearch([8, 2, 5, 4, 7, 0, 1, 6, 3], 5) # 2