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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.

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    int sumNumbers(TreeNode *root) {        vector<int> leaf;        int sum = 0;        if(root){            leafnum(root, leaf, 0);            int len = leaf.size();            for(int i=0;i<len; i++)                sum += leaf[i];            return sum;        }        return NULL;    }    void leafnum(TreeNode *root, vector<int> &leaf, int crt){        if(root->left == NULL && root->right == NULL){            leaf.push_back(root->val + crt * 10);            return;        }        if(root->left){            leafnum(root->left, leaf, root->val + crt * 10);        }        if(root->right){            leafnum(root->right, leaf, root->val + crt * 10);        }    }};

 

Sum Root to Leaf Numbers