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.
按照题目中的规则求出结果。
使用队列很容易可以得到结果。
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public int sumNumbers(TreeNode root) {
if( root == null )
return 0;
int result = 0;
Queue queue = new LinkedList<TreeNode>();
queue.add(root); while( !queue.isEmpty() ){ int size = queue.size();
for( int i = 0;i<size;i++){
TreeNode node = (TreeNode) queue.poll();
if( node.left != null ){
node.left.val = node.val*10+node.left.val;
queue.add(node.left);
}
if( node.right != null){
node.right.val = node.right.val+node.val*10;
queue.add(node.right);
}
if( node.left == null && node.right == null ){
result+=node.val;
}
} } return result; }
}