Created
April 19, 2010 20:15
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| def binary_search(list, match, index = 0) | |
| if list.empty? | |
| -1 | |
| else | |
| mid = list.length/2 | |
| case list[mid] <=> match | |
| when 0 | |
| index + mid | |
| when 1 | |
| binary_search(list[0...mid], match, index) | |
| when -1 | |
| binary_search(list[mid+1..-1], match, index + mid + 1) | |
| end | |
| end | |
| end |
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The range "mid+1..list.length" technically includes "list.length", which is not a valid index of "list". Although it does not hurt to include a range too big (values off the end will simply be ignored), it would be more accurate to use "...list.length", or "..list.length-1", or even simpler, "..-1".