Add a bunch of python exercises
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dotfiles/lib/python/add_up_to.py
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43
dotfiles/lib/python/add_up_to.py
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def count_unique_sums2(number, maximum_size):
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maximum_to_try = min(number, maximum_size) + 1
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the_range = list(range(1, maximum_to_try))
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all_sums = []
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for max_in_sum in the_range:
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if max_in_sum == number:
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all_sums.extend([[number]])
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continue
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new_sums = count_unique_sums(number-max_in_sum, max_in_sum)
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all_sums.extend(
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[
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sum_so_far + [max_in_sum]
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for sum_so_far in new_sums
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]
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)
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return all_sums
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unique_sum_counts = {}
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def count_unique_sums(number, maximum_size):
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if (number, maximum_size) in unique_sum_counts:
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return unique_sum_counts[(number, maximum_size)]
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maximum_to_try = min(number, maximum_size) + 1
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the_range = list(range(1, maximum_to_try))
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sum_count = 0
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for max_in_sum in the_range:
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if max_in_sum == number:
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sum_count += 1
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continue
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sum_count += count_unique_sums(number-max_in_sum, max_in_sum)
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unique_sum_counts[(number, maximum_size)] = sum_count
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return sum_count
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if __name__ == '__main__':
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print(count_unique_sums(100, 100))
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84
dotfiles/lib/python/lru_cache.py
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dotfiles/lib/python/lru_cache.py
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class Node(object):
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def __init__(self, key, value, next_node=None, prev_node=None):
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self.key = key
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self.value = value
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self.next_node = next_node
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self.prev_node = prev_node
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def print_list(self):
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print("{0} - {1}".format(self.key, self.value))
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if self.next_node is not None:
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assert self == self.next_node.prev_node
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self.next_node.print_list()
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else:
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print("next node is None")
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if self.prev_node is not None:
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assert self.prev_node.next_node == self
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class LRUCache(object):
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def __init__(self, capacity):
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self.capacity = capacity
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self.cache = {}
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self.head = None
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self.tail = None
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def put(self, key, value):
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"""
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If key already exists, replace the current value with the new value.
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If the key doesn't exist, add the new key/value entry to the cache.
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If the addition of the new entry causes the number of entries to exceed
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num_entries, remove the oldest entry based on the last time the entry is
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accessed (either through put or get).
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"""
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if key in self.cache:
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node = self.cache[key]
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node.value = value
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self.move_to_tail(node)
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return
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if len(self.cache) >= self.capacity:
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old_head = self.remove_from_head()
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del self.cache[old_head.key]
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new_node = Node(key, value)
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self.set_new_tail(new_node)
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self.cache[key] = new_node
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def set_new_tail(self, node):
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node.prev_node = self.tail
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if self.tail is not None:
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self.tail.next_node = node
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self.tail = node
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if self.head is None:
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self.head = node
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def move_to_tail(self, node):
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if node is self.tail:
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return
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if node.prev_node is None: # This is the head
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if node.next_node is not None:
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self.head = node.next_node
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node.next_node.prev_node = None
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else:
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node.prev_node.next_node = node.next_node
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node.next_node.prev_node = node.prev_node
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node.prev_node = self.tail
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self.tail.next_node = node
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self.tail = node
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self.tail.next_node = None
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def remove_from_head(self):
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previous_head = self.head
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self.head = self.head.next_node
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self.head.prev_node = None
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return previous_head
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def get(self, key):
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"""Return the value associated with the key, or None if the key doesn't
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exist."""
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node = self.cache.get(key)
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if node is not None:
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self.move_to_tail(node)
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return node.value
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29
dotfiles/lib/python/powerset.py
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dotfiles/lib/python/powerset.py
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import collections
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import copy
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def powerset(elems):
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counts = collections.defaultdict(int)
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for elem in elems:
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counts[elem] += 1
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return powerset_helper(counts.items())
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def powerset_helper(elems):
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last_generation = [[]]
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for (elem, count) in elems:
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next_generation = last_generation
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for _ in range(count):
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new_generation = []
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for subset in last_generation:
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new_subset = copy.copy(subset)
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new_subset.append(elem)
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new_generation.append(new_subset)
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next_generation.extend(new_generation)
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last_generation = new_generation
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last_generation = next_generation
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return last_generation
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if __name__ == '__main__':
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print(len(powerset(range(23))))
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31
dotfiles/lib/python/score_parentheses.py
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31
dotfiles/lib/python/score_parentheses.py
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#! /usr/bin/env python
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import sys
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def score_parentheses(input_string, index=0):
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if index >= len(input_string):
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return (0, index)
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if input_string[index] == '(':
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index += 1
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else:
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raise Exception("Invalid parentheses")
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children_score, index = score_children(input_string, index)
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if input_string[index] == ')':
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index += 1
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else:
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raise Exception("Invalid parentheses")
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return (children_score * 2 if children_score > 0 else 1, index)
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def score_children(input_string, index=0):
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input_length = len(input_string)
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children_score = 0
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while index < input_length and input_string[index] == '(':
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child_score, index = score_parentheses(input_string, index)
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children_score += child_score
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return (children_score, index)
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if __name__ == '__main__':
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print (score_children(sys.argv[1]))
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0
dotfiles/lib/python/sliding_median.py
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0
dotfiles/lib/python/sliding_median.py
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dotfiles/lib/python/sudoku.py
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dotfiles/lib/python/sudoku.py
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goodpuzzle = [
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[1,2,3,4,5,6,7,8,9],
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[4,5,6,7,8,9,1,2,3],
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[7,8,9,1,2,3,4,5,6],
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[2,3,4,5,6,7,8,9,1],
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[5,6,7,8,9,1,2,3,4],
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[8,9,1,2,3,4,5,6,7],
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[3,4,5,6,7,8,9,1,2],
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[6,7,8,9,1,2,3,4,5],
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[9,1,2,3,4,5,6,7,8]
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]
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badpuzzle1 = [
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[1,2,3,4,5,6,7,9,8],
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[4,5,6,7,8,9,1,2,3],
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[7,8,9,1,2,3,4,5,6],
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[2,3,4,5,6,7,8,9,1],
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[5,6,7,8,9,1,2,3,4],
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[8,9,1,2,3,4,5,6,7],
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[3,4,5,6,7,8,9,1,2],
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[6,7,8,9,1,2,3,4,5],
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[9,1,2,3,4,5,6,7,8]
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]
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badpuzzle2 = [
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[1,2,3,4,5,6,7,2,9],
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[4,5,6,7,8,9,1,8,3],
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[7,8,9,1,2,3,4,5,6],
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[2,3,4,5,6,7,8,9,1],
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[5,6,7,8,9,1,2,3,4],
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[8,9,1,2,3,4,5,6,7],
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[3,4,5,6,7,8,9,1,2],
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[6,7,8,9,1,2,3,4,5],
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[9,1,2,3,4,5,6,7,8]
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]
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badpuzzle3 = [
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[1,2,3,4,5,6,7,8,9],
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[4,5,6,7,8,9,1,2,3],
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[7,8,9,1,2,3,4,5,6],
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[2,3,4,5,6,7,8,9,1],
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[5,6,7,8,9,1,2,3,4],
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[3,4,5,6,7,8,9,1,2],
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[8,9,1,2,3,4,5,6,7],
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[6,7,8,9,1,2,3,4,5],
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[9,1,2,3,4,5,6,7,8]
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]
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one_to_nine = set(range(1, 10))
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def is_valid_sudoku_puzzle(sudoku_grid):
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for row in sudoku_grid:
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if set(row) != one_to_nine:
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return False
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for i in range(9):
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column = [sudoku_grid[j][i] for j in range(9)]
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if set(column) != one_to_nine:
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return False
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for i in range(3):
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for j in range(3):
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subgrid_elements = get_subgrid_elements(i, j, sudoku_grid)
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if set(subgrid_elements) != one_to_nine:
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return False
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return True
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def get_subgrid_elements(subgrid_row, subgrid_column, sudoku_grid, subgrid_size=3):
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subgrid_row_start = subgrid_row * subgrid_size
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subgrid_column_start = subgrid_column * subgrid_size
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subgrid_elements = []
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for i in range(subgrid_row_start, subgrid_row_start + subgrid_size):
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subgrid_elements += sudoku_grid[i][subgrid_column_start:subgrid_column_start+subgrid_size]
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return subgrid_elements
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print(is_valid_sudoku_puzzle(goodpuzzle))
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print(is_valid_sudoku_puzzle(badpuzzle1))
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print(is_valid_sudoku_puzzle(badpuzzle2))
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print(is_valid_sudoku_puzzle(badpuzzle3))
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