Python: Sort unsorted numbers using Patience sorting
Python Search and Sorting : Exercise-34 with Solution
Write a Python program to sort unsorted numbers using patience sorting.
From Wikipedia:
In computer science, patience sorting is a sorting algorithm inspired by, and named after, the card game patience. A variant of the algorithm efficiently computes the length of a longest increasing subsequence in a given array.
The algorithm's name derives from a simplified variant of the patience card game. The game begins with a shuffled deck of cards. The cards are dealt one by one into a sequence of piles on the table, according to the following rules.
1. nitially, there are no piles. The first card dealt forms a new pile consisting of the single card.
2. Each subsequent card is placed on the leftmost existing pile whose top card has a value greater than or equal to the new card's value, or to the right of all of the existing piles, thus forming a new pile.
3. When there are no more cards remaining to deal, the game ends.
Sample Solution:
Python Code:
#Ref.https://bit.ly/2YiegZB
from bisect import bisect_left
from functools import total_ordering
from heapq import merge
@total_ordering
class Stack(list):
def __lt__(self, other):
return self[-1] < other[-1]
def __eq__(self, other):
return self[-1] == other[-1]
def patience_sort(collection: list) -> list:
stacks = []
# sort into stacks
for element in collection:
new_stacks = Stack([element])
i = bisect_left(stacks, new_stacks)
if i != len(stacks):
stacks[i].append(element)
else:
stacks.append(new_stacks)
# use a heap-based merge to merge stack efficiently
collection[:] = merge(*[reversed(stack) for stack in stacks])
return collection
nums = [4, 3, 5, 1, 2]
print("\nOriginal list:")
print(nums)
patience_sort(nums)
print("Sorted order is:", nums)
nums = [5, 9, 10, 3, -4, 5, 178, 92, 46, -18, 0, 7]
print("\nOriginal list:")
print(nums)
patience_sort(nums)
print("Sorted order is:", nums)
Sample Output:
Original list: [4, 3, 5, 1, 2] Sorted order is: [1, 2, 3, 4, 5] Original list: [5, 9, 10, 3, -4, 5, 178, 92, 46, -18, 0, 7] Sorted order is: [-18, -4, 0, 3, 5, 5, 7, 9, 10, 46, 92, 178]
Flowchart:
Python Code Editor:
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