solution.js

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} s
 * @param {TreeNode} t
 * @return {boolean}
 */

// 判断两棵树是否相同
function isSame (t1, t2) {
    if (!t1 && !t2) {
        return true;
    }

    if (t1 && t2) {
        return t1.val === t2.val && isSame(t1.left, t2.left) && isSame(t1.right, t2.right);
    }

    return false;
}

var isSubtree = function (s, t) {
    const sequence = [];
    getNode(s, t.val);

    // 先筛出可能的节点作为根节点
    function getNode (node, val) {
        if (node.val === val) {
            sequence.push(node);
        }

        node.left && getNode(node.left, val);
        node.right && getNode(node.right, val);
    }

    return sequence.some((node) => {
        return isSame(node, t);
    });
};