code_binary_search.coffee (532B)
1 # Uses a binary search algorithm to locate a value in the specified array. 2 window.binary_search = (items, value) -> 3 4 start = 0 5 stop = items.length - 1 6 pivot = Math.floor (start + stop) / 2 7 8 while items[pivot] isnt value and start < stop 9 10 # Adjust the search area. 11 stop = pivot - 1 if value < items[pivot] 12 start = pivot + 1 if value > items[pivot] 13 14 # Recalculate the pivot. 15 pivot = Math.floor (stop + start) / 2 16 17 # Make sure we've found the correct value. 18 if items[pivot] is value then pivot else -1