100_Same_Tree.py

# Depth First Search
# Time complexity: O (n)
# Space complexity:O (n)

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right

class Solution:
    def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
        if not p and not q:
            return True
        if p and q and p.val == q.val:
            return self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)
        else:
            return False

# Breadth First Search
# Time complexity: O (n)
# Space complexity:O (n)


# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right

class Solution:
    def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
        q1 = deque([p])
        q2 = deque([q])

        while q1 and q2:
            nodeP = q1.popleft()
            nodeQ = q2.popleft()

            if nodeP is None and nodeQ is None:
                continue
            if nodeP is None or nodeQ is None or nodeP.val != nodeQ.val:
                return False

            q1.append(nodeP.left)
            q1.append(nodeP.right)
            q2.append(nodeQ.left)
            q2.append(nodeQ.right)

        return True