Main49.java

package JZOfferTuJi;

import java.util.LinkedList;
import java.util.Queue;

public class Main49 {
    public int sumNumbers(TreeNode root) {
        return dfs(root, 0);
    }

    public int dfs(TreeNode root, int prevSum){
        if(root == null){
            return 0;
        }
        prevSum = prevSum * 10 + root.val;
        if(root.left == null && root.right == null){
            return prevSum;
        }
        return dfs(root.left, prevSum) + dfs(root.right, prevSum);
    }
}

class Main49_1{
    public int sumNumbers(TreeNode root) {
        if(root == null){
            return 0;
        }
        int sum = 0;
        Queue<TreeNode> nodeQueue = new LinkedList<>();
        Queue<Integer> numQueue = new LinkedList<>();
        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;
    }
}