1305. 两棵二叉搜索树中的所有元素🔖DFS🔖数组

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root1
 * @param {TreeNode} root2
 * @return {number[]}
 */
var getAllElements = function(root1, root2) {
    let arr_left = []
    let arr_right = []
    let dfs = (data, arr) => {
        if (data) {
            dfs(data.left, arr)
            dfs(data.right, arr)
            arr.push(data.val)
        }
    }
    dfs(root1, arr_left)
    dfs(root2, arr_right)
    return arr_left.concat(arr_right).sort((a, b) => {return a - b})
};