mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-28 05:26:29 +08:00
1c0f350ad6
* Add the intial translation of code of all the languages * test * revert * Remove * Add Python and Java code for EN version
129 lines
4.1 KiB
Python
129 lines
4.1 KiB
Python
"""
|
|
File: array_deque.py
|
|
Created Time: 2023-03-01
|
|
Author: krahets (krahets@163.com)
|
|
"""
|
|
|
|
|
|
class ArrayDeque:
|
|
"""Double-ended queue class based on circular array"""
|
|
|
|
def __init__(self, capacity: int):
|
|
"""Constructor"""
|
|
self._nums: list[int] = [0] * capacity
|
|
self._front: int = 0
|
|
self._size: int = 0
|
|
|
|
def capacity(self) -> int:
|
|
"""Get the capacity of the double-ended queue"""
|
|
return len(self._nums)
|
|
|
|
def size(self) -> int:
|
|
"""Get the length of the double-ended queue"""
|
|
return self._size
|
|
|
|
def is_empty(self) -> bool:
|
|
"""Determine if the double-ended queue is empty"""
|
|
return self._size == 0
|
|
|
|
def index(self, i: int) -> int:
|
|
"""Calculate circular array index"""
|
|
# Implement circular array by modulo operation
|
|
# When i exceeds the tail of the array, return to the head
|
|
# When i exceeds the head of the array, return to the tail
|
|
return (i + self.capacity()) % self.capacity()
|
|
|
|
def push_first(self, num: int):
|
|
"""Front enqueue"""
|
|
if self._size == self.capacity():
|
|
print("Double-ended queue is full")
|
|
return
|
|
# Move the front pointer one position to the left
|
|
# Implement front crossing the head of the array to return to the tail by modulo operation
|
|
self._front = self.index(self._front - 1)
|
|
# Add num to the front
|
|
self._nums[self._front] = num
|
|
self._size += 1
|
|
|
|
def push_last(self, num: int):
|
|
"""Rear enqueue"""
|
|
if self._size == self.capacity():
|
|
print("Double-ended queue is full")
|
|
return
|
|
# Calculate rear pointer, pointing to rear index + 1
|
|
rear = self.index(self._front + self._size)
|
|
# Add num to the rear
|
|
self._nums[rear] = num
|
|
self._size += 1
|
|
|
|
def pop_first(self) -> int:
|
|
"""Front dequeue"""
|
|
num = self.peek_first()
|
|
# Move front pointer one position backward
|
|
self._front = self.index(self._front + 1)
|
|
self._size -= 1
|
|
return num
|
|
|
|
def pop_last(self) -> int:
|
|
"""Rear dequeue"""
|
|
num = self.peek_last()
|
|
self._size -= 1
|
|
return num
|
|
|
|
def peek_first(self) -> int:
|
|
"""Access front element"""
|
|
if self.is_empty():
|
|
raise IndexError("Double-ended queue is empty")
|
|
return self._nums[self._front]
|
|
|
|
def peek_last(self) -> int:
|
|
"""Access rear element"""
|
|
if self.is_empty():
|
|
raise IndexError("Double-ended queue is empty")
|
|
# Calculate rear element index
|
|
last = self.index(self._front + self._size - 1)
|
|
return self._nums[last]
|
|
|
|
def to_array(self) -> list[int]:
|
|
"""Return array for printing"""
|
|
# Only convert elements within valid length range
|
|
res = []
|
|
for i in range(self._size):
|
|
res.append(self._nums[self.index(self._front + i)])
|
|
return res
|
|
|
|
|
|
"""Driver Code"""
|
|
if __name__ == "__main__":
|
|
# Initialize double-ended queue
|
|
deque = ArrayDeque(10)
|
|
deque.push_last(3)
|
|
deque.push_last(2)
|
|
deque.push_last(5)
|
|
print("Double-ended queue deque =", deque.to_array())
|
|
|
|
# Access element
|
|
peek_first: int = deque.peek_first()
|
|
print("Front element peek_first =", peek_first)
|
|
peek_last: int = deque.peek_last()
|
|
print("Rear element peek_last =", peek_last)
|
|
|
|
# Element enqueue
|
|
deque.push_last(4)
|
|
print("Element 4 rear enqueued, deque =", deque.to_array())
|
|
deque.push_first(1)
|
|
print("Element 1 front enqueued, deque =", deque.to_array())
|
|
|
|
# Element dequeue
|
|
pop_last: int = deque.pop_last()
|
|
print("Rear dequeued element =", pop_last, ", deque after rear dequeue =", deque.to_array())
|
|
pop_first: int = deque.pop_first()
|
|
print("Front dequeued element =", pop_first, ", deque after front dequeue =", deque.to_array())
|
|
|
|
# Get the length of the double-ended queue
|
|
size: int = deque.size()
|
|
print("Double-ended queue length size =", size)
|
|
|
|
# Determine if the double-ended queue is empty
|
|
is_empty: bool = deque.is_empty()
|
|
print("Is the double-ended queue empty =", is_empty)
|