RandomizedQuickSort(arrayInt, middle + 1, last)
end
end
def RandomizedPartition(arrayInt, first, last)
i = rand(last - first + 1) + first
arrayInt[i], arrayInt[last] = arrayInt[last], arrayInt[i]
return Partition(arrayInt, first, last)
end
def Partition(arrayInt, first, last)
x = arrayInt[last]
i = first - 1
for j in first .. (last - 1)
if arrayInt[j] <= x
i += 1
arrayInt[i], arrayInt[j] = arrayInt[j], arrayInt[i] #exchange
end
end
arrayInt[i + 1], arrayInt[last] = arrayInt[last], arrayInt[i + 1]
return i + 1
end
RandomizedQuickSort(arrayInt, 0, arrayInt.length-1)
puts "The sorted array is: " + arrayInt.to_s
快速排序的利用了Ruby的语法糖的随机化版本：
#encoding: utf-8
#author: xu jin, 4100213
#date: Oct 20, 2012
#RandomizedQuickSort
#to sort an array by using randomized QuickSort
#example:
#The original array is：[14, 47, 46, 49, 82, 76, 92, 22, 44, 81, 59, 61]
#The sorted array is: [14, 22, 44, 46, 47, 49, 59, 61, 76, 81, 82, 92]
arrayInt = Array.new
index = 0
while (index < 12)
arrayInt[index] = rand(100) #produce 12 random number
index += 1
end
puts "The original array is：" + arrayInt.to_s
def RandomizedQuickSort(a)
i = rand(a.length)
a[i], a[a.length - 1] = a[a.length - 1], a[i]
(x=a.pop) ? RandomizedQuickSort(a.select{|i| i <= x}) + [x] + RandomizedQuickSort(a.select{|i| i > x}) : []
end
puts "The sorted array is: " + RandomizedQuickSort(arrayInt).to_s
