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Commit e7af6b1

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1 parent c5476ff commit e7af6b1

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3 files changed

+143
-41
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3 files changed

+143
-41
lines changed

‎.gitignore‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
1+
huawei

‎Data Structures and Algorithms/recursion.py‎

Lines changed: 36 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -23,19 +23,51 @@ def factorial(n):
2323
return factorial(n-1) * n
2424

2525
n = 3
26-
print(f'{n}! = {factorial(n)}')
26+
print(f'{n}! = {factorial(n)}\n')
2727

2828
# ####################
2929
# Fibonacci sequence
3030
# ####################
31-
def fib(n):
31+
def fibDP(n): ## downUp
32+
if n < 1: return 0
3233
if n <= 2: return 1
33-
return fib(n-1) + fib(n-2)
34+
dp = [0]*(n+1)
35+
dp[1] = dp[2] = 1
36+
i = 3
37+
while i <= n:
38+
dp[i] = dp[i-1] + dp[i-2]
39+
i += 1
40+
return dp[n]
3441

35-
n = 5
42+
n = 10
43+
print('1, 1, 2, 3, 5, 8, 13 ....')
44+
print(f'第 {n} 位斐波那契数是 {fibDP(n)}')
45+
46+
def fib(n):
47+
if n < 1: return 0
48+
a, b = 0, 1
49+
for _ in range(n):
50+
a, b = b, a+b
51+
return a
52+
n = 10
3653
print('1, 1, 2, 3, 5, 8, 13 ....')
3754
print(f'第 {n} 位斐波那契数是 {fib(n)}')
3855

56+
def fibRecursion(n): ## upDown
57+
def upDown(n):
58+
if n < 1: return 0
59+
if n <= 2:
60+
return 1
61+
if dp[n]: return dp[n]
62+
dp[n] = upDown(n-1) + upDown(n-2)
63+
return dp[n]
64+
dp = [0] * (n+1)
65+
return upDown(n)
66+
n = 10
67+
print('1, 1, 2, 3, 5, 8, 13 ....')
68+
print(f'第 {n} 位斐波那契数是 {fibRecursion(n)}\n')
69+
70+
3971
# ####################
4072
# reverse String
4173
# ####################

‎Data Structures and Algorithms/tree.py‎

Lines changed: 106 additions & 37 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
#==================================================
88

99
from typing import List
10-
10+
importcollections
1111
# Definition for a binary tree node.
1212
class TreeNode:
1313
def __init__(self, val=0, left=None, right=None):
@@ -20,16 +20,18 @@ def preorderTraversal(self, root: TreeNode) -> List[int]:
2020
if root is None: return []
2121
stack, res = [root], []
2222
while stack:
23-
tmp = stack.pop()
24-
res.append(tmp.val)
25-
if tmp.right: stack.append(tmp.right)
26-
if tmp.left: stack.append(tmp.left)
23+
node = stack.pop()
24+
res.append(node.val)
25+
if node.right:
26+
stack.append(node.right)
27+
if node.left:
28+
stack.append(node.left)
2729
return res
2830

2931
def preorderTraversalRecursion(self, root: TreeNode) -> List[int]:
3032
def preorder(root):
31-
if not root: return []
32-
res.append(root.val)
33+
if not root: return
34+
res.append(root.val)## 前序
3335
preorder(root.left)
3436
preorder(root.right)
3537
return res
@@ -44,16 +46,16 @@ def inorderTraversal(self, root: TreeNode) -> List[int]:
4446
while cur:
4547
stack.append(cur)
4648
cur = cur.left
47-
tmp = stack.pop()
48-
res.append(tmp.val)
49-
cur = tmp.right
49+
node = stack.pop()
50+
res.append(node.val)
51+
cur = node.right
5052
return res
5153

5254
def inorderTraversalRecursion(self, root: TreeNode) -> List[int]:
5355
def inorder(root):
54-
if not root: return []
56+
if not root: return
5557
inorder(root.left)
56-
res.append(root.val)
58+
res.append(root.val)## 中序
5759
inorder(root.right)
5860
return res
5961
res = []
@@ -69,41 +71,100 @@ def postorderTraversal(self, root: TreeNode) -> List[int]:
6971
res.append(node.val)
7072
else:
7173
stack.append((1, node))
72-
if node.right: stack.append((0, node.right))
73-
if node.left: stack.append((0, node.left))
74+
if node.right:
75+
stack.append((0, node.right))
76+
if node.left:
77+
stack.append((0, node.left))
7478
return res
7579

7680
def postorderTraversalRecursion(self, root: TreeNode) -> List[int]:
7781
def postorder(root):
78-
if not root: return []
82+
if not root: return
7983
postorder(root.left)
8084
postorder(root.right)
81-
res.append(root.val)
85+
res.append(root.val)## 后序
8286
return res
8387
res = []
8488
postorder(root)
8589
return res
8690

87-
def levelOrder(self, root: TreeNode) -> List[List[int]]:
91+
def levelTraversalLeft(self, root: TreeNode) -> List[List[int]]:
92+
if not root: return []
93+
res, queue = [], collections.deque()
94+
queue.append(root)
95+
while queue:
96+
n, level = len(queue), []
97+
for _ in range(n):
98+
node = queue.popleft()
99+
level.append(node.val)
100+
if node.left:
101+
queue.append(node.left)
102+
if node.right:
103+
queue.append(node.right)
104+
res.append(level)
105+
return res
106+
107+
def levelTraversalRight(self, root: TreeNode) -> List[List[int]]:
88108
if not root: return []
89-
res, q = [], [root]
90-
whileq:
91-
n=len(q)
92-
level = []
109+
res, queue = [], collections.deque()
110+
queue.append(root)
111+
whilequeue:
112+
n, level =len(queue), []
93113
for _ in range(n):
94-
node = q.pop(0)
114+
node = queue.popleft()
95115
level.append(node.val)
96-
if node.left: q.append(node.left)
97-
if node.right: q.append(node.right)
116+
if node.right:
117+
queue.append(node.right)
118+
if node.left:
119+
queue.append(node.left)
98120
res.append(level)
99121
return res
100122

123+
def levelTraversal(self, root: TreeNode, k=-1) -> List[List[int]]:
124+
if not root: return []
125+
res, queue = [], collections.deque()
126+
queue.append(root)
127+
while queue:
128+
n, level = len(queue), collections.deque()
129+
for _ in range(n):
130+
node = queue.popleft()
131+
if k == -1: ## 左 --> 右
132+
level.append(node.val)
133+
else: ## 右 --> 左
134+
level.appendleft(node.val)
135+
if node.left:
136+
queue.append(node.left)
137+
if node.right:
138+
queue.append(node.right)
139+
res.append(list(level))
140+
return res
141+
142+
def levelTraversalJagged(self, root: TreeNode, k=-1) -> List[List[int]]:
143+
if not root: return []
144+
res, queue = [], collections.deque()
145+
queue.append(root)
146+
while queue:
147+
n, level = len(queue), collections.deque()
148+
k *= -1
149+
for _ in range(n):
150+
node = queue.popleft()
151+
if k == -1: ## 左 --> 右
152+
level.append(node.val)
153+
else: ## 右 --> 左
154+
level.appendleft(node.val)
155+
if node.left:
156+
queue.append(node.left)
157+
if node.right:
158+
queue.append(node.right)
159+
res.append(list(level))
160+
return res
161+
101162
def maxDepth(self, root: TreeNode) -> int:
102163
def bottomUp(root):
103164
return 0 if not root else max(bottomUp(root.left), bottomUp(root.right)) + 1
104-
def topDown(root, depth):
165+
def topDown(root, depth=0):
105166
return depth if not root else max(topDown(root.left, depth+1), topDown(root.right, depth+1))
106-
return topDown(root, 0), bottomUp(root)
167+
return topDown(root), bottomUp(root)
107168

108169
mat = Solution()
109170
## 前序
@@ -115,6 +176,7 @@ def topDown(root, depth):
115176

116177
root.right = TreeNode(5)
117178
root.right.left = TreeNode(6)
179+
118180
print("\n前序输出:")
119181
print(mat.preorderTraversal(root))
120182
print(mat.preorderTraversalRecursion(root))
@@ -133,19 +195,19 @@ def topDown(root, depth):
133195
print(mat.inorderTraversalRecursion(root))
134196

135197
## 后序
136-
root = TreeNode(6)
198+
# root = TreeNode(6)
137199

138-
root.left = TreeNode(3)
139-
root.left.left = TreeNode(1)
140-
root.left.right = TreeNode(2)
200+
# root.left = TreeNode(3)
201+
# root.left.left = TreeNode(1)
202+
# root.left.right = TreeNode(2)
141203

142-
root.right = TreeNode(5)
143-
root.right.left = TreeNode(4)
144-
print("\n后序输出:")
145-
print(mat.postorderTraversal(root))
146-
print(mat.postorderTraversalRecursion(root))
204+
# root.right = TreeNode(5)
205+
# root.right.left = TreeNode(4)
206+
# print("\n后序输出:")
207+
# print(mat.postorderTraversal(root))
208+
# print(mat.postorderTraversalRecursion(root))
147209

148-
## 层序
210+
# ## 层序
149211
root = TreeNode(1)
150212

151213
root.left = TreeNode(2)
@@ -155,7 +217,14 @@ def topDown(root, depth):
155217
root.right = TreeNode(3)
156218
root.right.left = TreeNode(6)
157219
print("\n层序输出:")
158-
print(mat.levelOrder(root))
220+
print(mat.levelTraversalLeft(root))
221+
print(mat.levelTraversalRight(root))
222+
223+
print(mat.levelTraversal(root))
224+
print(mat.levelTraversal(root, 1))
225+
226+
print(mat.levelTraversalJagged(root))
227+
print(mat.levelTraversalJagged(root, 1))
159228

160229
print('\n最大树深度:')
161230
mat.maxDepth(root)

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