Module: SimplyUseful::Bsearch
- Defined in:
- lib/simply_useful/bsearch.rb
Instance Method Summary collapse
- #bfind(range = 0 ... self.length, &block) ⇒ Object
-
#bsearch_first(range = 0 ... self.length, &block) ⇒ Object
This method searches the FIRST occurrence which satisfies a condition given by a block in binary fashion and return the index of the first occurrence.
-
#bsearch_last(range = 0 ... self.length, &block) ⇒ Object
This method searches the LAST occurrence which satisfies a condition given by a block in binary fashion and return the index of the last occurrence.
-
#bsearch_lower_boundary(range = 0 ... self.length, &block) ⇒ Object
Return the lower boundary.
-
#bsearch_range(range = 0 ... self.length, &block) ⇒ Object
Return the search result as a Range object.
-
#bsearch_upper_boundary(range = 0 ... self.length, &block) ⇒ Object
Return the upper boundary.
Instance Method Details
#bfind(range = 0 ... self.length, &block) ⇒ Object
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# File 'lib/simply_useful/bsearch.rb', line 128 def bfind(range = 0 ... self.length, &block) pos = self.bsearch_first(range, &block) return nil if pos.nil? self[pos] end |
#bsearch_first(range = 0 ... self.length, &block) ⇒ Object
This method searches the FIRST occurrence which satisfies a condition given by a block in binary fashion and return the index of the first occurrence. Return nil if not found.
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# File 'lib/simply_useful/bsearch.rb', line 73 def bsearch_first (range = 0 ... self.length, &block) boundary = bsearch_lower_boundary(range, &block) if boundary >= self.length || yield(self[boundary]) != 0 return nil else return boundary end end |
#bsearch_last(range = 0 ... self.length, &block) ⇒ Object
This method searches the LAST occurrence which satisfies a condition given by a block in binary fashion and return the index of the last occurrence. Return nil if not found.
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# File 'lib/simply_useful/bsearch.rb', line 108 def bsearch_last (range = 0 ... self.length, &block) # `- 1' for canceling `lower + 1' in bsearch_upper_boundary. boundary = bsearch_upper_boundary(range, &block) - 1 if (boundary <= -1 || yield(self[boundary]) != 0) return nil else return boundary end end |
#bsearch_lower_boundary(range = 0 ... self.length, &block) ⇒ Object
Return the lower boundary. (inside)
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# File 'lib/simply_useful/bsearch.rb', line 50 def bsearch_lower_boundary (range = 0 ... self.length, &block) lower = range.first() -1 upper = if range.exclude_end? then range.last else range.last + 1 end while lower + 1 != upper mid = ((lower + upper) / 2).to_i # for working with mathn.rb (Rational) if yield(self[mid]) < 0 lower = mid else upper = mid end end return upper end |
#bsearch_range(range = 0 ... self.length, &block) ⇒ Object
Return the search result as a Range object.
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# File 'lib/simply_useful/bsearch.rb', line 122 def bsearch_range (range = 0 ... self.length, &block) lower = bsearch_lower_boundary(range, &block) upper = bsearch_upper_boundary(range, &block) return lower ... upper end |
#bsearch_upper_boundary(range = 0 ... self.length, &block) ⇒ Object
Return the upper boundary. (outside)
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# File 'lib/simply_useful/bsearch.rb', line 85 def bsearch_upper_boundary (range = 0 ... self.length, &block) lower = range.first() -1 upper = if range.exclude_end? then range.last else range.last + 1 end while lower + 1 != upper mid = ((lower + upper) / 2).to_i # for working with mathn.rb (Rational) if yield(self[mid]) <= 0 lower = mid else upper = mid end end return lower + 1 # outside of the matching range. end |