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New leetcode
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‎562077_1441438125469_C3CB91D00CEB6F14114E695667CBE3B1.jpeg

67.4 KB
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‎CLRS/.DS_Store

6 KB
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‎CLRS/BLACKBOARD.txt

Whitespace-only changes.

‎CLRS/BST_insert.py

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# coding=utf-8
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def insert(head, x):
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"""
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:二分搜索树插入函数的实现
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:type head: 二分搜索树头节点
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:type x: 需要插入的树的节点
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"""
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fir, sec = head, None
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# 搜索确定x应该安放的具体位置, fir最后指向的None
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# 即为最后的应安放的位置
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while fir != None:
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sec = fir
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if x.val < fir.val:
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fir = fir.left
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else: fir = fir.right
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# 第一种判定是否树本身为空
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# 第二种判定x值小于sec
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# 第三种判定x值大于sec
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# 对插入节点进行插入判断和安置
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if sec == None:
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head = x
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elif sec.val > x.val:
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sec.left = x
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else:
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sec.right = x
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return head # 返回头节点

‎CLRS/CS 180 Textbook.pdf

4.84 MB
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‎CLRS/LCS.py

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def findLCS(A, n, B, m):
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# write code here
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c = [([0] * (m + 1)) for _ in xrange(n + 1)]
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for i in xrange(n):
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for j in xrange(m):
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if A[i] == B[j]:
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c[i + 1][j + 1] = c[i][j] + 1
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elif c[i][j + 1] > c[i + 1][j]:
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c[i + 1][j + 1] = c[i][j + 1]
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else:
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c[i + 1][j + 1] = c[i + 1][j]
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return c[n][m]
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print findLCS("1A2C3D4B56",10,"B1D23CA45B6A",12)

‎CLRS/RB-STD.txt

+113
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LF-RT(T, x)
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y = x.right
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x.right = y.left
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if y.left != T.nil
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y.left.parent = x
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y.parent = x.parent
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if x.parent == T.nil
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T.root = y
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elif x.parent.right = x
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x.parent.right = y
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else
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x.parent.left = y
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y.left = x
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x.parent = y
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RB-TRANSPLANT(T, u, v)
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if u.parent == T.nil
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T.root = v
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elif u.parent.right == u
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u.parent.right = v
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else
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u.parent.left = v
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v.parent = u.parent
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RB-INSERT(T, z)
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x = T.root
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y = T.nil
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while x != T.nil
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y = x
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if x.val < z.val
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x = x.right
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else
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x = x.left
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z.parent = y.parent
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if y == T.nil
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T.root = z
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elif y.parent.right == y
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y.parent.right = z
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else
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y.parent.left = z
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z.left = T.nil
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z.right = T.nil
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z.color = RED
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RB-INSERT-FIX(T, z)
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RB-INSERT-FIX(T, z)
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while z.parent.color == RED
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if z.parent = z.parent.parent.left
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y = z.parent.parent.right
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if y.color == RED
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y.color = BLACK
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z.parent.color = BLACK
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z.parent.parent.color = RED
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z = z.parent.parent
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elif z = z.parent.right
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z = z.parent
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LF-RT(T, z)
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z.parent.color = BLACK
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z.parent.parent.color = RED
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RT-RT(T, z.parent.parent)
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else (change left and right)
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T.root.color = BLACK
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RB-DELETE(T, z)
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y = z
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y-ori-color = z.color
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if z.right == T.nil
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x = z.right
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TRANSPLANT(T, z, z.right)
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elif z.left == T.nil
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x = z.left
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TRANSPLANT(T, z, z.left)
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else
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y = TREE-MIN(T, z.right)
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y-ori-color = y.color
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x = y.right
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if y.parent == z
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x.parent = y
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else
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TRANSPLANT(T, y, y.right)
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y.right = z.right
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y.right.parent = y
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TRANSPLANT(T, z, y)
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y.left = z.left
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y.left.parent = y
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y.color = z.color
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if y-ori-color == BLACK
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RB-DELETE-FIX(T, x)
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RB-DELETE-FIX(T, x)
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while T.root != x and x.color == BLACK
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if x == x.parent.left
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w = x.parent.right
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if w.color == RED
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w.color = BLACK
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x.parent.color = RED
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LF.RT(x.parent)
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w = x.parent.right
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if w.left.color == BLACK and w.right.color == BLACK
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w.color = RED
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x = x.parent
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elif w.right.color == BLACK
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w.color = RED
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w.left.color = BLACK
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RT-RT(T, w)
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w = x.parent.right
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w.color = x.parent.color
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w.right.color = BLACK
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x.parent.color = BLACK
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LF-RT(T, x.parent)
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T.root = x
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else(change left and right)
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x.color = BLACK

‎CLRS/cut-rod.py

+22
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# coding=utf-8
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# 切钢条问题的迭代解
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# def cut_rod(price, n):
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# """""""""""""""""
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# :切钢条问题动态规划O(n^2)解
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# :price type: list
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# :n type: integer
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# """""""""""""""""
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# res = [0] * (n + 1)
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# for i in xrange(1, n + 1):
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# q = -30000 # 此值只是为了代替python最小值
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# for j in xrange(1, i + 1):
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# q = max(q, price[j] + res[i - j])
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# res[i] = q
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# return res[n]
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if __name__ == '__main__':
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price = [0, 1, 5, 8, 9, 10, 17, 17, 20, 24, 30]
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print cut_rod(price, 10)

‎CLRS/red-black-tree.py

+201
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# coding=utf-8
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# CLRS中红黑树的Python实现
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class TreeNode(object):
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def __init__(self, x):
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self.val = x
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self.left = None
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self.right = None
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self.color = None
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self.parent = None
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class Red_Black_Tree(object):
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def __init__(self):
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"""""""""
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:构造函数
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:root作为头节点指针
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:dummy作为尾部空节点存在
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"""""""""
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self.root = None
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self.dummy = TreeNode(None)
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self.dummy.color = 'Black'
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def insert(self, z):
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"""""""""
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:插入函数
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:z type: TreeNode
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"""""""""
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x = self.root
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y = self.dummy
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while x != self.dummy:
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y = x
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if x.val < z.val:
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x = x.right
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else:
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x = x.left
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z.parent = y
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if y == self.dummy:
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self.root = z
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elif y.val < z.val:
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y.right = z
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else:
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y.left = z
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z.left = self.dummy
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z.right = self.dummy
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z.color = 'Red'
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self.insert_fix(z)
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def insert_fix(self, z):
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"""""""""
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:插入修正函数
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:z type: TreeNode
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"""""""""
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while z.parent.color == 'Red':
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if z.parent.parent.left == z.parent:
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y = z.parent.parent.right
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if y.color == 'Red':
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y.color = 'Black'
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z.parent.color = 'Black'
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z.parent.parent.color = 'Red'
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z = z.parent.parent
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else:
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if z == z.parent.right:
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z = z.parent
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self.left_rotate(z)
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z.parent.color = 'Black'
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z.parent.parent.color = 'Red'
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self.right_rotate(z.parent.parent)
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else:
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y = z.parent.parent.left
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if y.color == 'Red':
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y.color = 'Black'
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z.parent.color = 'Black'
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z.parent.parent.color = 'Red'
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z = z.parent.parent
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else:
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if z == z.parent.left:
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z = z.parent
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self.right_rotate(z)
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z.parent.color = 'Black'
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z.parent.parent.color = 'Red'
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self.left_rotate(z.parent.parent)
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self.root.color = 'Black'
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def delete(self, z):
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"""""""""
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:删除函数
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:z type: TreeNode
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"""""""""
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y = z
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y_ori_color = z.color
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if z.left == self.dummy:
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x = z.right
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self.transplant(z, z.right)
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elif z.right == self.dummy:
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x = z.left
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self.transplant(z, z.left)
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else:
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y = self.tree_min(z.right) # tree_min函数还没写
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y_ori_color = y.color
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x = y.right
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if y.parent == z:
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x.parent = y
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else:
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self.transplant(y, y.right)
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y.right = z.right
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y.right.parent = y
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self.transplant(z, y)
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y.left = z.left
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y.left.parent = y
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y.color = z.color
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if y_ori_color == 'Black':
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self.delete_fix(x)
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def delete_fix(self, x):
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"""""""""
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:删除修正函数
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:x type: TreeNode
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"""""""""
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while self.dummy != x and x.color == 'Black':
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if x.parent.left == x:
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w = x.parent.right
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if w.color == 'Red':
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w.color = 'Black'
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x.parent.color = 'Red'
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self.left_rotate(x.parent)
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w = x.parent.right
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if w.left.color == 'Black' and w.right.color == 'Black':
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w.color = 'Red'
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x = x.parent
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else:
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if w.right.color == 'Black':
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w.left.color = 'Black'
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w.color = 'Red'
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self.right_rotate(w)
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w = x.parent.right
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w.color = x.parent.color
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w.right.color = 'Black'
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x.parent.color = 'Black'
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self.left_rotate(x.parent)
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self.root = x
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else:
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w = x.parent.left
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if w.color == 'Red':
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w.color = 'Black'
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x.parent.color = 'Red'
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self.right_rotate(x.parent)
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w = x.parent.left
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if w.left.color == 'Black' and w.right.color == 'Black':
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w.color = 'Red'
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x = x.parent
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else:
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if w.left.color == 'Black':
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w.right.color = 'Black'
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w.color = 'Red'
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self.left_rotate(w)
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w = x.parent.left
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w.color = x.parent.color
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w.left.color = 'Black'
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x.parent.color = 'Black'
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self.right_rotate(x.parent)
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self.root = x
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x.color = 'Black'
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def transplant(self, u, v):
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"""""""""
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:移植函数
168+
:u type: TreeNode
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:v type: TreeNode
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"""""""""
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if u.parent == self.dummy:
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self.root = v
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elif u.parent.left == u:
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u.parent.left = v
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else:
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u.parent.right = v
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v.parent = u.parent
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def left_rotate(self, z):
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"""""""""
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:左转函数
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:z type: TreeNode
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"""""""""
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y = z.right
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z.right = y.left
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if y.left != None:
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y.left.parent = z
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y.parent = z.parent
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if z.parent == self.dummy:
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self.root = y
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elif z.parent.left == z:
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z.parent.left = y
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else:
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z.parent.right = y
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y.left = z
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z.parent = y
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if __name__ == '__main__':
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a = Red_Black_Tree()
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# print a.dummy.color

‎CLRS/台大课件/.DS_Store

6 KB
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