LeetCode 112. Path Sum dynamic presentation

To a target value, it is determined whether a tree from the root to leaves combined with at least one path is equal to the target value

The typical depth-first algorithm.

The introduction of a global variable bResult, once one is found, it is no longer a search for the other.

class Solution {
public:
    void helper(TreeNode* cur, int sum, int target, bool& bResult){
        if(bResult)
            return;
        
        //a(cur)
        //lk("root",cur)
        //a(sum)
        //a(target)
        //dsp
        if(!cur->left && !cur->right){
            bResult|= target-sum==cur->val;
        }
        
        if(cur->left)
            helper(cur->left, sum+cur->val, target, bResult);        
                
        if(cur->right)
            helper(cur->right, sum+cur->val, target, bResult);
        
    }
    
    bool hasPathSum(TreeNode* root, int sum) {        
        if(!root)
            return false;
        
        if(!root->left && !root->right){
            return sum==root->val;
        }
        
        //ahd(root)
        bool bRet=false;
        //a(bRet)
        
        if(root->left)
            helper(root->left, root->val, sum, bRet);
        
        if(root->right)
            helper(root->right, root->val, sum, bRet);
        
        //dsp
        return bRet;
        
    }
};

Running dynamic presentation  http://simpledsp.com/FS/Html/lc112.html