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July 5, 2012 22:19
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StackOverflow - Ruby - Optimize the comparison of two arrays with duplicates
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#!/usr/bin/env ruby | |
# benchmarks for http://stackoverflow.com/questions/11349544/ruby-optimize-the-comparison-of-two-arrays-with-duplicates/11352055#comment14951595_11352055 | |
require 'rubygems' | |
require 'multiset' | |
require 'benchmark' | |
small_b = "cheddaar".split(//) | |
small_a = "cheddar".split(//) | |
BIG_A_SZ = 10_000 | |
big_b = (0...BIG_A_SZ).to_a | |
big_a = big_b.dup | |
big_a.delete_at(rand(BIG_A_SZ)) | |
N = 100_000 | |
BIGN = 10 | |
def op_del_subset(a,b) | |
aa = a.dup | |
b.each do |letter| | |
aa.delete_at(aa.index(letter)) rescue "" | |
end | |
aa.empty? | |
end | |
def ct_subset(a,b) | |
a_counts = a.reduce(Hash.new(0)) { |m,v| m[v] += 1; m } | |
b_counts = b.reduce(Hash.new(0)) { |m,v| m[v] += 1; m } | |
a_counts.all? { |a_key,a_ct| a_ct <= b_counts[a_key] } | |
end | |
def ct_acc_subset(a,b) | |
counts = a.reduce(Hash.new(0)) { |m,v| m[v] += 1; m } | |
b.each { |v| counts[v] -= 1 } | |
counts.values.all? { |ct| ct <= 0 } | |
end | |
def mset_subset(a,b) | |
Multiset.new(a).subset? Multiset.new(b) | |
end | |
def slow_ct_subset(a,b) | |
!a.find{|x| a.count(x) > b.count(x)} | |
end | |
cases = %w{ op_del ct ct_acc mset slow_ct } | |
Benchmark.bm(15) do |bm| | |
a, b = small_a, small_b | |
cases.each do |test| | |
meth = :"#{test}_subset" | |
bm.report("s_#{test}") { N.times{ send(meth, a, b); send(meth, b, a) } } | |
end | |
a, b = big_a, big_b | |
cases.each do |test| | |
meth = :"#{test}_subset" | |
bm.report("b_#{test}") { BIGN.times{ send(meth, a, b); send(meth, b, a) } } | |
end | |
a, b = small_a, big_b | |
cases.each do |test| | |
meth = :"#{test}_subset" | |
bm.report("sb_#{test}") { BIGN.times{ send(meth, a, b); send(meth, b, a) } } | |
end | |
end |
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