Created
March 8, 2013 02:37
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| import random | |
| def main(): | |
| a = AVLTree() | |
| for i in range(0, 100): | |
| # print '-----------------------------------' | |
| a.insert(random.randrange(0, 100000)) | |
| a.pr() | |
| assert len(list(a.traverse())) == 100, len(list(a.traverse())) | |
| for v in a.traverse(): | |
| print v, | |
| class AVLTree(object): | |
| def __init__(self): | |
| self.root = None | |
| def insert(self, value): | |
| if self.root is None: | |
| self.root = A(value) | |
| return | |
| self.root = self.root.insert(A(value)) | |
| def traverse(self): | |
| for node in self.root.traverse(): | |
| yield node.value | |
| def pr(self): | |
| self.root.pr() | |
| class A(object): | |
| def __init__(self, value): | |
| self.value = value | |
| self.left = None | |
| self.right = None | |
| self.height = 1 | |
| def count(self): | |
| count = 1 | |
| if self.left: | |
| count += self.left.count() | |
| if self.right: | |
| count += self.right.count() | |
| return count | |
| def traverse(self): | |
| if self.left: | |
| for node in self.left.traverse(): | |
| yield node | |
| yield self | |
| if self.right: | |
| for node in self.right.traverse(): | |
| yield node | |
| def root(self): | |
| pass | |
| def pr(self, tab_level=0): | |
| print '\t' * tab_level, '-', self.value, '(', self.height, ')', \ | |
| '(', self.balance, ')', (self.ll , self.rl) | |
| if self.left: | |
| self.left.pr(tab_level=tab_level+1) | |
| else: | |
| print '\t' * (tab_level+1), '-', 'NONE' | |
| if self.right: | |
| self.right.pr(tab_level=tab_level+1) | |
| else: | |
| print '\t' * (tab_level+1), '-', 'NONE' | |
| @property | |
| def ll(self): | |
| if self.left is None: | |
| return 0 | |
| return self.left.height | |
| @property | |
| def rl(self): | |
| if self.right is None: | |
| return 0 | |
| return self.right.height | |
| @property | |
| def balance(self): | |
| return self.ll - self.rl | |
| def insert(self, a): | |
| # print 'INS', a.value, 'into', self.value | |
| # Insert | |
| if a.value < self.value: | |
| if self.left: | |
| self.left = self.left.insert(a) | |
| else: | |
| self.left = a | |
| else: | |
| if self.right: | |
| self.right = self.right.insert(a) | |
| else: | |
| self.right = a | |
| self.height = max(self.ll, self.rl) + 1 | |
| return self.rebalance() | |
| def rebalance(self): | |
| # Rebalance | |
| diff = self.ll - self.rl | |
| if abs(self.balance) < 2: | |
| return self | |
| assert -2 <= self.balance <= 2 | |
| if self.balance == -2: | |
| rb = 0 if not self.right else self.right.balance | |
| assert -1 <= rb <= 1 | |
| if rb == 1: | |
| self.right = self.right.right_rotation() | |
| res = self.left_rotation() | |
| return res | |
| elif self.balance == 2: | |
| lb = 0 if not self.left else self.left.balance | |
| assert -1 <= lb <= 1 | |
| if lb == -1: | |
| self.left = self.left.left_rotation() | |
| return self.right_rotation() | |
| assert False | |
| def reset_height(self): | |
| self.height = max(self.rl, self.ll) + 1 | |
| def left_rotation(self): | |
| right = self.right | |
| right_left = None if not right else right.left | |
| if not right: | |
| return self | |
| self.right = right_left | |
| right.left = self | |
| self.reset_height() | |
| right.reset_height() | |
| return right | |
| def right_rotation(self): | |
| left = self.left | |
| left_right = None if not left else left.right | |
| if not left: | |
| return self | |
| self.left = left_right | |
| left.right = self | |
| self.reset_height() | |
| left.reset_height() | |
| return left | |
| main() |
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