TheAlgorithms-Ruby/sorting/heap_sort.rb
2020-11-03 19:05:15 +09:00

31 lines
No EOL
971 B
Ruby

# Algorithm: Heap-Sort
# Time-Complexity: O(nlogn)
def heap_sort(array)
array_size = array.size
adjusted_array = [nil] + array
(array_size / 2).downto(1) do |i|
adjusted_down(adjusted_array, i, array_size)
end
while array_size > 1
adjusted_array[1], adjusted_array[array_size] = adjusted_array[array_size], adjusted_array[1]
array_size -= 1
adjusted_down(adjusted_array, 1, array_size)
end
adjusted_array.drop(1)
end
#Method to adjust heap in downward manner
def adjusted_down(adjusted_array, parent, limit)
top = adjusted_array[parent]
while (child = 2 * parent) <= limit
child += 1 if child < limit and adjusted_array[child] < adjusted_array[child + 1]
break if top >= adjusted_array[child]
adjusted_array[parent] = adjusted_array[child]
parent = child
end
adjusted_array[parent] = top
end
#Code for testing heapsort
array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15].shuffle
print heap_sort(array)