Created
October 23, 2010 22:40
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Binary search implemented in coffeescript.
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| binary_search = (val, L) -> | |
| return false if L.length == 0 | |
| mid = Math.floor(L.length / 2) | |
| if L[mid] == val | |
| return mid | |
| else if val > L[mid] | |
| binary_search(val, L[(mid + 1)..(L.length)]) | |
| else | |
| binary_search(val, L[0..(mid - 1)]) | |
| list = [1,2,3,4,5,6,7,8] | |
| alert binary_search(18, list) # false | |
| alert binary_search(3, list) # 2 | |
| alert binary_search(6, list) # 5 |
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Wouldn't line 5's
return midjust constantly return 1?Here's an example at each level:
Assume val = 2
mid = floor ( 9 / 2 ) = 4
mid = floor ( 4 / 2 ) = 2
mid = floor ( 2 / 2 ) = 1
if L[mid] == val matches and we now return 1