叶子相似的树

/**
 * 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}
 */
var leafSimilar = function(root1, root2) {
    var dfs = function(root, target) {
        if(!root) return ;
        if(!root.left && !root.right) {
            target.push(root.val);
            return ;
        }
        if(root.left) dfs(root.left, target);
        if(root.right) dfs(root.right, target);
    }
    var target1 = [];
    var target2 = [];
    dfs(root1, target1);
    dfs(root2, target2);
    var n1 = target1.length;
    var n2 = target2.length;
    if(n1 !== n2) return false;
    for(let i=0;i<n1;++i){
        if(target1[i] !== target2[i]) return false;
    }
    return true;
};