LeetCode - 100. Same Tree

real_lisa

于 2019-06-28 16:56:05 发布

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本文链接：https://blog.youkuaiyun.com/real_lisa/article/details/94008975

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本文介绍了两种判断二叉树是否相同的算法实现：迭代法和递归法。通过使用deque来存储节点，迭代法逐层比较两棵树的节点值；递归法则直接比较当前节点及其左右子树。两种方法均返回布尔值，表示两棵树是否完全一致。

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100. Same Tree

Iterative

# 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 isSameTree(self, p, q):
        """
        :type p: TreeNode
        :type q: TreeNode
        :rtype: bool
        """
        que1, que2 = collections.deque([p]), collections.deque([q])
        while(que1 and que2):
            n1 = que1.popleft()
            n2 = que2.popleft()
            if n1 and n2:
                if n1.val != n2.val:
                    return False
                que1.append(n1.left)
                que2.append(n2.left)
                que1.append(n1.right)
                que2.append(n2.right)
            elif n1 != n2:
                return False
        return True

Recursion

# 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 isSameTree(self, p, q):
        """
        :type p: TreeNode
        :type q: TreeNode
        :rtype: bool
        """
        if p and q:
            if p.val != q.val: return False
            else: return self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)
        return p == q