Created
July 30, 2015 00:56
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def findIndex(values, target) | |
binarySearch(values, target, 0, values.size - 1) | |
end | |
def binarySearch(values, target, start, finish) | |
return -1 if start > finish | |
middle = ((start+finish)/2).floor | |
value = values[middle] | |
puts "From #{start} to #{finish}. Middle: #{middle}" | |
return binarySearch(values, target, start, middle-1) if value > target | |
return binarySearch(values, target, middle+1, finish) if value < target | |
puts "Result: #{middle}" | |
return middle | |
end | |
findIndex([2, 4, 6, 8, 10, 12, 14, 16, 18, 20], 6) | |
# => | |
# From 0 to 9. Middle: 4 | |
# From 0 to 3. Middle: 1 | |
# From 2 to 3. Middle: 2 | |
# Result: 2 |
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