require 'benchmark/ips'

def find_one_using_group_by_select(array)
 array.group_by{ |e| e }.detect { |k, v| k if v.size > 1 }&.first
end

def find_one_using_chunk_select(array)
 array.sort.chunk{ |e| e }.detect { |e, chunk| chunk.size > 1 }&.first
end

def find_one_using_count_select(array)
  array.detect{ |e| array.count(e) > 1 }
end

def find_one_using_hash_map(array)
  map = {}
  dup = nil
  array.each do |v|
    map[v] = (map[v] || 0 ) + 1

    if map[v] > 1
      dup = v
      break
    end
  end

  return dup
end

def find_all_using_group_by_select(array)
  array.group_by{ |e| e }.select { |k, v| k if v.size > 1 }.map &:first
end

def find_all_using_chunk_select(array)
  array.sort.chunk{ |e| e }.select { |e, chunk| chunk.size > 1 }.map &:first
end

def find_all_using_count_select(array)
  array.select{ |e| array.count(e) > 1 }.uniq
end

def find_all_using_hash_map(array)
  map = {}
  dup = []
  array.each do |v|
    map[v] = (map[v] || 0 ) + 1

    if map[v] == 2
      dup << v
    end
  end

  return dup
end

num_array = Array.new(1000) { rand 1000 }
char_array = Array.new(20) { (65 + rand(26)).chr }
word_array = Array.new(1000) { Array.new(5) { (65 + rand(26)).chr }.join }

Benchmark.ips do |x|
  puts "Find one uniq element from: Number array"

  x.report('Using group_by.select') do
    find_one_using_group_by_select(num_array)
  end

  x.report('Using sort.chunk.select') do
    find_one_using_chunk_select(num_array)
  end

  x.report('Using count select') do
    find_one_using_count_select(num_array)
  end

  x.report('Using hash map') do
    find_one_using_hash_map(num_array)
  end

  x.compare!
end

Benchmark.ips do |x|
  puts "Find one uniq element from: Character array"

  x.report('Using group_by.select') do
    find_one_using_group_by_select(char_array)
  end

  x.report('Using sort.chunk.select') do
    find_one_using_chunk_select(char_array)
  end

  x.report('Using count select') do
    find_one_using_count_select(char_array)
  end

  x.report('Using hash map') do
    find_one_using_hash_map(char_array)
  end

  x.compare!
end



Benchmark.ips do |x|
  puts "Find one uniq element from: Word array"

  x.report('Using group_by.select') do
    find_one_using_group_by_select(word_array)
  end

  x.report('Using sort.chunk.select') do
    find_one_using_chunk_select(word_array)
  end

  x.report('Using count select') do
    find_one_using_count_select(word_array)
  end

  x.report('Using hash map') do
    find_one_using_hash_map(word_array)
  end

  x.compare!
end

Benchmark.ips do |x|
  puts "Find all uniq elements from: Number array"

  x.report('Using group_by.select') do
    find_all_using_group_by_select(num_array)
  end

  x.report('Using sort.chunk.select') do
    find_all_using_chunk_select(num_array)
  end

  x.report('Using count select') do
    find_all_using_count_select(num_array)
  end

  x.report('Using hash map') do
    find_all_using_hash_map(num_array)
  end

  x.compare!
end

Benchmark.ips do |x|
  puts "Find all uniq elements from: Character array"

  x.report('Using group_by.select') do
    find_all_using_group_by_select(char_array)
  end

  x.report('Using sort.chunk.select') do
    find_all_using_chunk_select(char_array)
  end

  x.report('Using count select') do
    find_all_using_count_select(char_array)
  end

  x.report('Using hash map') do
    find_all_using_hash_map(char_array)
  end

  x.compare!
end



Benchmark.ips do |x|
  puts "Find all uniq elements from: Word array"

  x.report('Using group_by.select') do
    find_all_using_group_by_select(word_array)
  end

  x.report('Using sort.chunk.select') do
    find_all_using_chunk_select(word_array)
  end

  x.report('Using count select') do
    find_all_using_count_select(word_array)
  end

  x.report('Using hash map') do
    find_all_using_hash_map(word_array)
  end

  x.compare!
end