Java for LeetCode 129 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
.
解题思路:
递归,JAVA实现如下:
static public int sumNumbers(TreeNode root) { if(root==null) return 0; return sumNumbers(root,0); } public static int sumNumbers(TreeNode root,int res) { if(root.left==null&&root.right==null) return res*10+root.val; if(root.left==null) return sumNumbers(root.right,res*10+root.val); if(root.right==null) return sumNumbers(root.left,res*10+root.val); return sumNumbers(root.left,res*10+root.val)+sumNumbers(root.right,res*10+root.val); }
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