LeetCode 129. Sum Root to Leaf Numbers dynamic presentation

Value tree is [0, 9], each path from the root to the leaf constitutes an integer, (the first number is the root), find all integers and all components of the

Depth-first search, by accumulating a integer parameter

 

class Solution {
public:    
    void helper(TreeNode* node, int path, int& sum){
        if(!node){
            return;
        }
        //a(node)
        //lk("root",node)
        //a(path)
        //dsp
        if(!node->left && !node->right){
            sum+=path*10+node->val;
            //dsp
            return;
        }
        
        helper(node->left, path*10+node->val, sum);        
        helper(node->right, path*10+node->val, sum);        
    }
    
    int sumNumbers(TreeNode* root) {
        int sum=0;
        //ahd(root)
        //a(sum)
        helper(root, 0, sum);
        return sum;
    }
};

Running dynamic presentations: http://simpledsp.com/FS/Html/lc129.html