Created
July 22, 2015 17:06
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A balanced BST
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class BalancedBst | |
module Empty | |
extend self | |
def <<(data) | |
BalancedBst.new data | |
end | |
def >>(data) | |
self | |
end | |
def each | |
self | |
end | |
def inspect | |
"" | |
end | |
end | |
def initialize(data, left=Empty, right=Empty) | |
@data, @left, @right, @current = data, left, right, [:left, :right] | |
end | |
def <<(data) | |
@current.first == :left ? | |
insert_left(data) : | |
insert_right(data) | |
@current.rotate! | |
self | |
end | |
def each(&block) | |
@left.each &block | |
block.call @data | |
@right.each &block | |
end | |
def inspect | |
llines = @left.inspect.lines.map(&:chomp) | |
rlines = @right.inspect.lines.map(&:chomp) | |
num_lines = [llines.length, rlines.length].max | |
(num_lines - llines.length).times { llines << "" } | |
(num_lines - rlines.length).times { rlines << "" } | |
line_length = [*llines, *rlines, ""].map(&:length).max | |
lines = llines.zip(rlines).map { |lline, rline| | |
lline.chomp.rjust(line_length, ' ') << ' ' << rline.chomp.ljust(line_length, ' ') << "\n" | |
} | |
[ @data.inspect.center(line_length*2+1, ' ') << "\n", | |
*lines | |
].join | |
end | |
private | |
def insert_left(data) | |
if data < @data | |
@left <<= data | |
else | |
@left <<= @data | |
@data = data | |
end | |
end | |
def insert_right(data) | |
if data < @data | |
@right <<= @data | |
@data = data | |
else | |
@right <<= data | |
end | |
end | |
end | |
tree = BalancedBst::Empty | |
15.times { |i| | |
tree <<= i | |
# => 0 | |
# | |
# , 1 | |
# 0 | |
# | |
# , 1 | |
# 0 2 | |
# | |
# , 3 | |
# 1 2 | |
# 0 | |
# | |
# , 3 | |
# 1 4 | |
# 0 2 | |
# | |
# , 5 | |
# 1 4 | |
# 0 3 2 | |
# | |
# , 5 | |
# 1 4 | |
# 0 3 2 6 | |
# | |
# , 7 | |
# 5 4 | |
# 1 3 2 6 | |
# 0 | |
# | |
# , 7 | |
# 5 8 | |
# 1 3 4 6 | |
# 0 2 | |
# | |
# , 9 | |
# 5 8 | |
# 1 7 4 6 | |
# 0 3 2 | |
# | |
# , 9 | |
# 5 8 | |
# 1 7 4 10 | |
# 0 3 2 6 | |
# | |
# , 11 | |
# 9 8 | |
# 1 7 4 10 | |
# 0 5 3 2 6 | |
# | |
# , 11 | |
# 9 12 | |
# 1 7 4 10 | |
# 0 5 3 2 8 6 | |
# | |
# , 13 | |
# 9 12 | |
# 1 7 4 10 | |
# 0 5 3 11 2 8 6 | |
# | |
# , 13 | |
# 9 12 | |
# 1 7 4 10 | |
# 0 5 3 11 2 8 6 14 | |
} | |
tree | |
# => 13 | |
# 9 12 | |
# 1 7 4 10 | |
# 0 5 3 11 2 8 6 14 |
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