标签:style blog http color io os ar for sp
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
.
top-down 显然很直接. 可以改变每个node的值. 如果不想改变可以添加一个path.在函数参数里.
/** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { public int sumNumbers(TreeNode root) { int[] result = {0}; int path = 0; GenerateSum(root,result,path); return result[0]; } void GenerateSum(TreeNode root, int[] result, int path){ if(root == null){ return; } path = path*10 + root.val; if(root.left == null && root.right == null){ result[0] += path; return; } GenerateSum(root.left,result,path); GenerateSum(root.right,result,path); } }
标签:style blog http color io os ar for sp
原文地址:http://www.cnblogs.com/leetcode/p/4003794.html