Subtree of Another Tree
Given two binary trees root and subRoot (as level-order arrays), return True if subRoot is a subtree of root.
A subtree is a node and all its descendants matching exactly.
Example:
3,4,5,1,2 4,1,2
True
- The binary tree
rootis constructed from the level-order array: 3,4,5,1,2, resulting in a tree with 3 as the root, 4 and 5 as its children, and 1 and 2 as children of 4. - The binary tree
subRootis constructed from the level-order array: 4,1,2, resulting in a tree with 4 as the root and 1 and 2 as its children. - We then check if
subRootis a subtree ofrootby comparing the structure and node values ofsubRootwith the corresponding subtree ofrootrooted at node 4. - Since the subtree of
rootrooted at node 4 has the same structure and node values assubRoot, we conclude thatsubRootis a subtree ofroot, resulting in an output ofTrue.
Constraints:
- 1 <= nodes in root <= 2000
- 1 <= nodes in subRoot <= 1000
- -10^4 <= Node.val <= 10^4
Background Knowledge
The problem involves two binary trees, root and subRoot, and the goal is to determine if subRoot is a subtree of root. To approach this problem, it's essential to understand the basic structure and properties of binary trees. A binary tree is a data structure in which each node has at most two children (i.e., left child and right child). This structure allows for efficient traversal and searching of the tree.
In the context of this problem, a subtree is defined as a node and all its descendants that match exactly. This means that if subRoot is a subtree of root, then the structure and values of subRoot must be identical to a subset of nodes in root. To solve this problem, you'll need to understand how to traverse binary trees and compare their structures. Tree traversal techniques, such as pre-order, in-order, and post-order traversal, will be crucial in comparing the structures of the two trees.
The problem also involves comparing the structures of two trees, which requires understanding the concept of tree isomorphism. Two trees are isomorphic if they have the same structure, i.e., the same number of nodes and edges, and the same connections between nodes. However, in this problem, we're looking for a subtree, which means we need to find a subset of nodes in root that is isomorphic to subRoot.
Algorithm/Approach
The general approach to solving this problem involves using a combination of tree traversal and subtree comparison. One possible algorithm pattern is to traverse the root tree and, for each node, check if the subtree rooted at that node is identical to subRoot. This can be done by using a recursive function to compare the structures of the two trees.
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