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May 3, 2011 13:19
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Selection Sort in ruby
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# Selection sort (very slow on large lists) | |
a = [9,8,6,1,2,5,4,3,9,50,12,11] | |
n = a.size - 1 | |
n.times do |i| | |
index_min = i | |
(i + 1).upto(n) do |j| | |
index_min = j if a[j] < a[index_min] | |
end | |
# Yep, in ruby I can do that, no aux variable. w00t! | |
a[i], a[index_min] = a[index_min], a[i] if index_min != i | |
end |
My ruby version of selection sort:
def selection_sort(arr)
(arr.size-1).times do |index|
tmp_item, tmp_index = arr[index], index
for i in index...arr.size
tmp_item, tmp_index = arr[i], i if arr[i] < tmp_item
end
arr[index], arr[tmp_index] = arr[tmp_index], arr[index]
end
arr
end
great
def selection_sort(arr)
n = arr.length - 1
n.times do |i|
min_index = i
((i + 1)..n).each do |j|
min_index = j if arr[j] < arr[min_index]
end
arr[i], arr[min_index] = arr[min_index], arr[i] if min_index != i
end
arr
end
arr = [2, 5, 6, 2, 5425, 54, 5, 4, 12, 7, 3, 5, 5]
print selection_sort(arr)
Love it!
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Is the
if index_min != i
needed at the end? Cuzif == index
_min then you just swap it with itself so it will work even without that condition.