leetcode--Sum Root to Leaf Numbers
Given a binary tree containing digits from 0-9
only, each root-to-leaf path could represent a number.
An example is the root-to-leaf path 1->2->3
which represents the number 123
.
Find the total sum of all root-to-leaf numbers.
For example,
1 / \ 2 3
The root-to-leaf path 1->2
represents the number 12
.
The root-to-leaf path 1->3
represents the number 13
.
Return the sum = 12 + 13 = 25
.
/** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { /**This problem is just an implementation of bfs<br> *The algorithm is straightforward:<br> * @author Averill Zheng * @version 2014-06-02 * @since JDK 1.7 */ public int sumNumbers(TreeNode root) { int sum = 0; Queue<TreeNode> node = new LinkedList<TreeNode>(); Queue<Integer> number = new LinkedList<Integer>(); if(root != null){ node.add(root); number.add(root.val); while(node.peek() != null){ TreeNode aNode = node.poll(); int num = number.poll(); if(aNode.left != null){ node.add(aNode.left); number.add(num * 10 +aNode.left.val); } if(aNode.right != null){ node.add(aNode.right); number.add(num * 10 +aNode.right.val); } if(aNode.left == null && aNode.right == null){ sum += num; } } } return sum; } }