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101_symmetricTree.py
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classSolution(object):
# Queue
defisSymmetric(self, root):
ifnotroot:
returnTrue
queue= [(root.left, root.right)]
whilequeue:
left, right=queue.pop(0)
ifnotleftandnotright:
continue
ifnotleftornotright:
returnFalse
ifleft.val!=right.val:
returnFalse
queue.append((left.left, right.right))
queue.append((left.right,right.left))
returnTrue
# Recursion
defisSymmetric2(self, root):
ifnotroot:
returnTrue
defdfs(left, right):
ifnotleftandnotright:
returnTrue
ifnotleftornotright:
returnFalse
ifleft.val!=right.val:
returnFalse
returndfs(left.left , right.right) anddfs(left.right, right.left)
returndfs(root.left, root.right)
