def canFinish(self, numCourses: int, prerequisites: List[List[int]]) -> bool:
if not prerequisites:
return True
n = numCourses
graph = [set() for _ in range(n)]
in_degree = [0] * n
for p in prerequisites:
graph[p[1]].add(p[0])
in_degree[p[0]] += 1
queue = deque([])
for i in range(n):
if in_degree[i] == 0:
queue.append(i)
count = 0
while queue:
tmp = queue.popleft()
count += 1
if count == n:
return True
for j in graph[tmp]:
in_degree[j] -= 1
if in_degree[j] == 0:
queue.append(j)
return False
def __init__(self):
self.memory_buffer = deque(maxlen=2000)
self.gamma = 0.95
self.epsilon = 1
self.epsilon_decay = 0.95
self.epsilon_min = 0.01
self.env = gym.make('Cartpole-v0')
def _init_(slef, buffer_size, batch_size):
"""Initializer a ReplayBuffer object.
Params
=====
buffer_size: maxium size of buffer
batch_size: size of each training batch
"""
self.memory = deque(maxlen=buffer_size) # internal memory
self.batch_size = batch_size
self.experience = namedtuple("Experience", field_names=["state", "action", "reward", "next_state", "done"])
def BFS(graph,u):
visited=set()
queue = deque()
queue.append(u)
visited.add(u)
while len(queue)!=0:
s = queue.popleft()
print (s, end = " ")
for i in graph[s]:
if i not in visited:
queue.append(i)
visited.add(i)
def bfs(start):
q = deque()
q.append(start)
visited.append(start)
while q:
dat = q.pop()
for i in graph[dat]:
if i not in visited:
visited.append(i)
q.append(i)
def FindPartsOfIsland(M, i, j, c, r):
q = deque()
q.append([i, j])
while (len(q) != 0):
i = q.pop()
x = i[0]
y = i[1]
if (M[x][y] == 1):
M[x][y] = 2
appendIF(q, r, c, x + 1, y)
appendIF(q, r, c, x, y + 1)
appendIF(q, r, c, x - 1, y)
appendIF(q, r, c, x, y - 1)
def bfs(computer):
queue = deque()
queue.append(1)
count = 0
# 큐가 진행되는 동안
while queue:
v = queue.popleft()
# 현재 주어진 컴퓨터에 연결된 컴퓨터 찾기
for com in computer[v]:
if virus[com] == 0:
virus[com] = 1
queue.append(com)
count += 1
return count
def joinall(threads):
from collection import deque
from sys import getswitchinterval
interval = getswitchinterval()
threads = deque(threads)
while threads:
t = threads[0]
t.join(timeout=interval)
if not t.is_alive():
threads.popleft()
yield t
else:
threads.rotate(-1)
def BFS(v): from collection import deque queue = deque() queue.append(v) seen[v] = 1 parent[v] = -1 while queue: v = queue.popleft() for neighbor in graph[v]: if not seen[neighbor]: queue.append(neighbor) distance[neighbor] = distance[v] + 1 parent[neighbor] = v seen[neighbor] = 1
def depthFirst2(startingNode, soughtValue):
visitedNodes = set()
queue = deque([startingNode])
while len(queue) > 0:
node = queue.pop()
if node in visitedNodes:
continue
visitedNodes.add(node)
if node.value == soughtValue:
return True
for n in node.adjacentNodes:
if n not in visitedNodes:
queue.appendleft(n)
return False
def widthOfBinaryTree(self, root: TreeNode) -> int:
if not root:
return 0
res = 1
# q = deque((root, 0)) # q:[root, 0]
q = deque()
# The key to solve the problem though lie on how we index the nodes that are on the same level.
q.append((root, 0)) # q:[(root, 0)]
while q:
level_length = len(q)
_, level_head_index = q[0]
for _ in range(level_length):
node, col_index = q.popleft()
if node.left:
q.append([node.left, 2 * col_index])
if node.right:
q.append([node.right, 2 * col_index + 1])
res = max(res, col_index - level_head_index + 1)
return res
def ladderLength(beginWord, endWord, wordList):
"""
:type beginWord: str
:type endWord: str
:type wordList: List[str]
:rtype: int
"""
wordList = set(wordList)
alpha = ascii_lowercase
visited = set()
q = collection.deque()
q.append([beginWord,1])
while q:
cur_word, length = q.popleft()
if cur_word == endWord:
return length
for i in range(len(cur_word)):
for ch in alpha:
new_word = cur_word[:i]+ch+cur_word[i+1:]
if new_word in wordList and new_word not in visited:
q.append([new_word,length+1))
visited.add(new_word)
return 0
def mostDifferentNums(root):
q = deque([root])
maxLevel = {}
while len(q) > 0:
uniqueNodesInLevel = set()
toBeAdded = []
while len(q) > 0:
curr = q.popleft()
if curr not in uniqueNodesInLevel:
maxLevel[curr.val] = maxLevel.get(curr.val, 0) + 1
uniqueNodesInLevel.add(curr.val)
toBeAdded.append(curr)
for i in toBeAdded:
if i.left:
q.append(i.left)
if i.right:
q.append(i.right)
maxVal = -1
maxNode = None
for key, val in maxLevel:
if val > maxVal:
maxVal = val
maxNode = key
return maxNode
"""
BFS Template
neighbor 表示从某个点 head 出发，可以走到的下一层的节点。
set 存储已经访问过的节点（已经丢到 queue 里去过的节点）
queue 存储等待被拓展到下一层的节点
set 与 queue 是一对好基友，无时无刻都一起出现，往 queue 里新增一个节点，就要同时丢到 set 里。
无需分层：即问题不需要我区分开不同层级的结果信息
"""
from collection import deque
queue = deque() # list-like container with fast appends and pops on either end
seen = set()
seen.add(start)
queue.append(start)
while len(queue):
head = queue.popleft() # Pop out the first element in the queue
for neighbor in head.neighbors: #以head为起点，其附近所有的neighbor都检查一遍
if neighbor not in seen:
seen.add(neighbor)
queue.append(neighbor)
"""
BFS Template
neighbor 表示从某个点 head 出发，可以走到的下一层的节点。
''' Collection that support adding and removing items LIFO Example: Order Processing, Messaging ''' from collection import deque queue = deque() # Inserting the data into queue queue.append(1) queue.append(2) queue.append(33) queue.append(6) queue.append(17) print(queue) # Poping the data from left x = queue.popleft() print(x) print(queue)
def __init__(self):
self.items = deque()
plt.waitforbuttonpress()
plt.close('all')
test_videos_dir = join('data', 'test_videos')
test_videos = [join(test_videos_dir, name) for name in os.listdir(test_videos_dir)]
for test_video in test_videos:
print('Processing video: {}'.format(test_video))
cap = cv2.VideoCapture(test_video)
out = cv2.VideoWriter(join('out', 'videos', basename(test_video)),
fourcc = cv2.VideoWriter_fourcc(*'DIVX'),
fps = 20.0, frameSize= (resize_w, resize_h))
frame_buffer = deque(maxlen=10)
while cap.isOpened():
ret, color_frame = cap.read()
if ret:
color_frame = cv2.cvtColor(color_frame, cv2.COLOR_BGR2RGB)
color_frame = cv2.resize(color_frame, (resize_w, resize_h))
frame_buffer.append(color_frame)
blend_frame = color_frame_pipeline(frames = frame_buffer, solid_lines = True, temporal_smoothing= True)
out.write(cv2.cvtColor(blend_frame, cv2.COLOR_RGB2BGR))
cv2.imshow('blend', cv2.cvtColor(blend_frame, cv2.COLOR_RGB2BGR))
cv2.waitKey(1)
else:
break
cap.release()
out.release()
cv2.destroyAllWindows()
floats *=.5
floats[-3:]
from time import perf_counter as pc
t0 = pc();
floats /=3;
pc() - t0
numpy.save('floats-10M.npy', 'r+')
floats2 = numpy.load('floats-10M.npy','r+')
floats2 *=6
floats2[-3:]
# Trabalhando com um deque
from collection import deque
dq = deque(range(10), maxlen=10)
dq
dq.rotate(3)
dq
dq.rotate(-4)
dq
dq.appendleft(-1)
dq
dq.extend([11,22,33])
dq
dq.extendleft([10,20,30,40])
dq
# Se estivermos lidando com lista de números, arrays é mais prático.
# Usamos muito mais lista porque é bem mais prático.
from collection import deque
class PuzzelState (object):
def __str__ (self):
r = ""
i = 0
for tile in self.gamestate:
r += str(tile) + ""
if i % 3:
i += "\n"
i += 1
return r
working = deque()
visited = []
working.append(initial)
while len(working):
cur = working.popleft()
if cur == goalstate:
break
stateleft =cur.moveLeft()
if stateleft not in visited:
working.append(stateleft)
visited.append(stateleft)
# do the same for other states
# Стек: last in, first out # Очередь: first in, first out # Медленная очередь — список queue_slow = [] queue_slow.append(5) queue_slow.append(10) queue_slow.append(7) print(queue_slow) # [5, 10, 7] x = queue_slow.pop(0) # O(N) по времени! print(x) # 5 print(queue_slow) # [10, 7] # Тяжёлая очередь queue_big = list(range(100000000)) q_start = 0 # remove превращается в две операции # мы не удаляем элемент из памяти, а просто сдвигаемся x = queue_big[q_start] # O(1) q_start += 1 # O(1) # быстро, но требует всегда держать резерв памяти занятым # Наиболее эффективная — в библиотеке deque from collection import deque queue = deque(range(10000000)) queue.append(1) x = queue.popleft() # медленнее, чем предыдущее, но всё равно очень быстро # можно написать самим через двусвязный список
from collection import deque
import requests
from bs4 import BeautifulSoup
from urllib.parse import urlparse, urljoin
base_url = 'http://register.start.bg/'
links = deque()
links.append(base_url)
visited = set()
while len(links) > 0:
link = links.pop()
visited.add(link)
r = requests.get(link)
html = r.text
msg = link
soup = BeautifulSoup(html, 'html.parser')
for tag in soup.find_all('a'):
if tag.get('href') is not None and '#' not in tag.get('href'):
tag = tag.get('href')
if 'http' in tag:
links.append(tag)
else:
tag = urljoin(msg, tag)
links.append(tag)
# for item in visited:
# r = requests.get(item, verify=False, timeout=5)
def __init__(self):
self.cat_queue = deque()
self.dog_queue = deque()
self.order = 0
MSFT_x = MSFT_x.drop(['Date', 'Up_Down', 'Firm', 'Rating', 'Firm_Rating'],
axis=1)
#building RNN
import tensorflow as tf
import keras
from keras.layers import Dense, Dropout, LSTM #for output and layers
from keras.models import Sequential # for RNN
from keras.utils import to_categorical
#choosing interval to predict and sequence length
seq_len = 60
fut_pred = 3
#pred_var = "" #fill in
prev_days = deque(maxlen=seqlen)
#cutting last 10 % of data to predict on
L_10 = MSFT_x[int(0.9 * len(MSFT_x.index)):]
test_x = MSFT_x[:int(0.9 * len(MSFT_x.index)) + 1]
#create a future column
fut_class = []
for i in list(range(0, (len(MSFT_x.index) - 3))):
v = 0
if MSFT_x['Adj Close'][i + 3] > MSFT_x['Adj Close'][i]:
v = 1
else:
v = 0
fut_class.append(v)
['Mg Mg', 'Aye Aye', 'Mya Mya', 'Ko Ko', 'Phyu Phyu', 'Ni Ni']
>>> student.remove('Mya Mya')
>>> student
['Mg Mg', 'Aye Aye', 'Ko Ko', 'Phyu Phyu', 'Ni Ni']
>>> student.pop()
'Ni Ni'
>>> student
['Mg Mg', 'Aye Aye', 'Ko Ko', 'Phyu Phyu']
>>> from collection import deque
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'collection'
>>> from collections import deque
>>> queue = deque(["Eric", "John", "Micheal"])
>>> queue.append('Terry')
>>> queue.append('Graham')
>>> queue
deque(['Eric', 'John', 'Micheal', 'Terry', 'Graham'])
>>> queue.popleft()
'Eric'
>>> queue.popleft()
'John'
>>> queue
deque(['Micheal', 'Terry', 'Graham'])
>>>
>>> cube = []
>>> for i in range(10):
def search(lines, pattern, history=5):
previous_lines = deque(maxlen=history)
for line in lines:
if pattern in line:
yield line, previous_lines
previous_lines.append(line)
def serch(lines,pattern,history=5):
previous_lines = deque(maxlen = history)
for li in lines:
if pattern in li :
yield li, previous_lines # 生成器函数
previous_lines.append(li)
Queure: first in first out
from collection import deque
q = deque(['nikita','darshan','unnati'])
q.append('shreyas')
q.popleft()
print(q)
print(lsit(q))
output::
deque(['darshan','unnati','shreyas'])
['darshan','unnati','shreyas']
def __init__(self, lines, histlen=3):
self.lines = lines
self.history = deque(maxlen=hislen)
