/examples/computer_science/binary_search.coffee
http://github.com/jashkenas/coffee-script · CoffeeScript · 25 lines · 13 code · 7 blank · 5 comment · 5 complexity · c2ff8a0bb6d2152427809982f7b7330e MD5 · raw file
- # Uses a binary search algorithm to locate a value in the specified array.
- binary_search = (items, value) ->
- start = 0
- stop = items.length - 1
- pivot = Math.floor (start + stop) / 2
- while items[pivot] isnt value and start < stop
- # Adjust the search area.
- stop = pivot - 1 if value < items[pivot]
- start = pivot + 1 if value > items[pivot]
- # Recalculate the pivot.
- pivot = Math.floor (stop + start) / 2
- # Make sure we've found the correct value.
- if items[pivot] is value then pivot else -1
- # Test the function.
- console.log 2 is binary_search [10, 20, 30, 40, 50], 30
- console.log 4 is binary_search [-97, 35, 67, 88, 1200], 1200
- console.log 0 is binary_search [0, 45, 70], 0
- console.log -1 is binary_search [0, 45, 70], 10