Java 代码

class Solution {

    // Encodes a tree to a single string.
    String serialize(TreeNode root) {
        StringBuilder sb = new StringBuilder();
        LinkedList<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        while(!queue.isEmpty()) {
            TreeNode node = queue.poll();
            if (node == null) {
                sb.append("#,");
            }else {
                sb.append(node.val + ",");
            }
            if (node != null) {
                queue.offer(node.left);
                queue.offer(node.right);
            }
        }
        sb.deleteCharAt(sb.length() - 1);
        return sb.toString();
    }

    // Decodes your encoded data to tree.
    TreeNode deserialize(String data) {
        if (data.length() <= 0)
            return null;

        String[] strs = data.split(",");
        if ("#".equals(strs[0]))
            return null;
        TreeNode root = new TreeNode(Integer.valueOf(strs[0]));
        LinkedList<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        int idx = 1;
        while (idx < strs.length && !queue.isEmpty()) {
            TreeNode work = queue.poll();
            if (!"#".equals(strs[idx])) {
                work.left = new TreeNode(Integer.valueOf(strs[idx]));
                queue.offer(work.left);
            }
            idx++;
            if (!"#".equals(strs[idx])) {
                work.right = new TreeNode(Integer.valueOf(strs[idx]));
                queue.offer(work.right);
            }
            idx++;
        }
        return root;
    }
}