题目要求
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.
代码实现
/**
* Definition for binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
int res = 0;
public int sumNumbers(TreeNode root) {
if(root == null){
return 0;
}
sum(root,0);
return res;
}
public void sum(TreeNode node,int tmp){
tmp = tmp * 10 + node.val;
if(node.left==null&&node.right==null){
res += tmp;
}
if(node.left!= null){
sum(node.left,tmp);
}
if(node.right!=null){
sum(node.right,tmp);
}
}
}
