Java | Leetcode Java题解之第129题求根节点到叶节点数字之和

题目：

题解：

class Solution {public int sumNumbers(TreeNode root) {if (root == null) {return 0;}int sum = 0;Queue<TreeNode> nodeQueue = new LinkedList<TreeNode>();Queue<Integer> numQueue = new LinkedList<Integer>();nodeQueue.offer(root);numQueue.offer(root.val);while (!nodeQueue.isEmpty()) {TreeNode node = nodeQueue.poll();int num = numQueue.poll();TreeNode left = node.left, right = node.right;if (left == null && right == null) {sum += num;} else {if (left != null) {nodeQueue.offer(left);numQueue.offer(num * 10 + left.val);}if (right != null) {nodeQueue.offer(right);numQueue.offer(num * 10 + right.val);}}}return sum;}
}