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jashkenas--coffeescript/examples/beautiful_code/binary_search.coffee

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CoffeeScript

# Beautiful Code, Chapter 6.
# The implementation of binary search that is tested.
# Return the index of an element in a sorted list. (or -1, if not present)
index = (list, target) ->
[low, high] = [0, list.length]
while low < high
mid = (low + high) >> 1
val = list[mid]
return mid if val is target
if val < target then low = mid + 1 else high = mid
return -1
console.log 2 is index [10, 20, 30, 40, 50], 30
console.log 4 is index [-97, 35, 67, 88, 1200], 1200
console.log 0 is index [0, 45, 70], 0