Leetcode Note: Sum Root to Leaf Numbers

Leetcode Note: Sum Root to Leaf Numbers

I. Description

Given a binary tree containing digits from 0-9 only, each root-to-leaf path cocould 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 path1->2Represents the number12.
The root-to-leaf path1->3Represents the number13.

Returnsum = 12 + 13 = 25.

Ii. Question Analysis

This question is just a binary tree deep Priority Search question. When the leaf node points, the node values from the root to the leaf node path constitute a decimal number, in essence, it is still a deep-first search question.

Iii. Sample Code

#include 
  
   struct TreeNode{    int val;    TreeNode *left;    TreeNode *right;    TreeNode(int x) : val(x), left(NULL), right(NULL) {}};class Solution{    void sumNumbers(TreeNode*root, int &Result, int &TmpResult)    {        if (!root)        {            return;        }        // update the TmpResult        TmpResult = TmpResult * 10 + root->val;        if (!root->left && !root->right)        {            Result += TmpResult;        }        if (root->left)        {            sumNumbers(root->left, Result, TmpResult);        }        if (root->right)        {            sumNumbers(root->right, Result, TmpResult);        }        // restore the TmpResult;        TmpResult = (TmpResult - root->val) / 10;    }public:    int sumNumbers(TreeNode* root)    {        int Result = 0;        int TmpResult = 0;        sumNumbers(root, Result, TmpResult);        return Result;    }};
  

Iv. Summary

This question is a problem of deformation of binary tree deep priority search. It is the recursive traversal of binary tree, but it is just a different method.