叶子相似的树

叶子相似的树:https://leetcode-cn.com/problems/leaf-similar-trees/
总体思路：对二叉树进行遍历并将其叶子节点通过字符串拼接到一起，通过字符串对比输出结果

class Solution {
public  boolean leafSimilar(TreeNode root1, TreeNode root2) {
        String r1=traverse(root1);
        String r2=traverse(root2);
        System.out.println(r1);
        System.out.println(r2);
        if(r1.equals(r2))
            return true;
        return false;
}

public  String traverse(TreeNode root){
    if(root==null)
        return null;
    String left="";
    TreeNode t=root;
    LinkedList<TreeNode> starck=new LinkedList<>();
    while(t!=null||!starck.isEmpty()){
        if(t!=null){
            starck.push(t);
            if(t!=null&&(t.left==null)&&(t.right==null)){
                left+=t.val;
            }
            t=t.left;
        }else{
            t=starck.pop();
            t=t.right;
        }

    }
    return left;
}

}