100. 相同的树

class Solution:
    def isSameTree(self, p, q):
        """
        :type p: TreeNode
        :type q: TreeNode
        :rtype: bool
        """
        if p==None and q==None:
            return True
        if p==None or q==None:
            return False
        if p.val==q.val:
            return self.isSameTree(p.left,q.left) and self.isSameTree(p.right,q.right)
        else:
            return False