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.
Note: A leaf is a node with no children.
Example:
1 2 3 4 5 6 7 8 9
Input: [1,2,3] 1 / 2 3 Output: 25 Explanation: The root-to-leaf path 1->2 represents the number 12. The root-to-leaf path 1->3 represents the number 13. Therefore, sum = 12 + 13 = 25.
Example 2:
1 2 3 4 5 6 7 8 9 10 11 12
Input: [4,9,0,5,1] 4 / 9 0 / 5 1 Output: 1026 Explanation: The root-to-leaf path 4->9->5 represents the number 495. The root-to-leaf path 4->9->1 represents the number 491. The root-to-leaf path 4->0 represents the number 40. Therefore, sum = 495 + 491 + 40 = 1026.
解法:
这个题要求把二叉树路径上的所有数字序列转换成实数并进行求和,直观的思路就是通过存下一个个路径上的数字,随后进行求和即可完成问题,但是直接使用 int 会产生数字大小溢出的情况,所以需要使用unsigned long long int存储求和过程中应有的结果,同时需要记得对每一层使用过的 num 进行还原,避免影响其它层的求解;
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