Leaf-Similar Trees

Description

Consider all the leaves of a binary tree, from left to right order, the values of those leaves form a leaf value sequence.

For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8).

Two binary trees are considered leaf-similar if their leaf value sequence is the same.

Return true if and only if the two given trees with head nodes root1 and root2 are leaf-similar.

 

Example 1:

Input: root1 = [3,5,1,6,2,9,8,null,null,7,4], root2 = [3,5,1,6,7,4,2,null,null,null,null,null,null,9,8]
Output: true

Example 2:

Input: root1 = [1], root2 = [1]
Output: true

Example 3:

Input: root1 = [1], root2 = [2]
Output: false

Example 4:

Input: root1 = [1,2], root2 = [2,2]
Output: true

Example 5:

Input: root1 = [1,2,3], root2 = [1,3,2]
Output: false

 

Constraints:

• The number of nodes in each tree will be in the range [1, 200].
• Both of the given trees will have values in the range [0, 200].

Solution(javascript)

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root1
 * @param {TreeNode} root2
 * @return {boolean}
 */
const leafSimilar = (root1, root2) => {
  const traverse = (node, leaves) => {
    if (!node) {
      return leaves
    }
    if (node.left) {
      leaves.push(...traverse(node.left, []))
    }
    if (!node.left && !node.right) {
      leaves.push(node.val)
    }
    if (node.right) {
      leaves.push(...traverse(node.right, []))
    }
    return leaves
  }
  const leaves1 = traverse(root1, [])
  const leaves2 = traverse(root2, [])
  return leaves1.every((l1, index) => l1 === leaves2[index])
}