572. Subtree of Another Tree

572. Subtree of Another Tree

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def isSubtree(self, s, t):
        """
        :type s: TreeNode
        :type t: TreeNode
        :rtype: bool
        """
        if s == None:
            return False
        if self.isSame(s, t):
            return True
        else:
            return self.isSubtree(s.left, t) or self.isSubtree(s.right, t)
    def isSame(self, s, t):
        if s == None and t == None:
            return True
        elif s == None or t == None:
            return False
        elif s.val != t.val:
            return False
        else:
            return self.isSame(s.left, t.left) and self.isSame(s.right, t.right)

如果是判断子结构，不是子树

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def isSubtree(self, s, t):
        """
        :type s: TreeNode
        :type t: TreeNode
        :rtype: bool
        """
        if s == None:
            return False
        if self.isSame(s, t):
            return True
        else:
            return self.isSubtree(s.left, t) or self.isSubtree(s.right, t)
    def isSame(self, s, t):
        if t == None:
            return True
        elif s == None:
            return False
        elif s.val != t.val:
            return False
        else:
            return self.isSame(s.left, t.left) and self.isSame(s.right, t.right)