LeetCode 112 Path Sum

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

Note: A leaf is a node with no children.

Example:

Given the below binary tree and sum = 22,

return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.

 

 

c++

class Solution {
public:
    bool hasPathSum(TreeNode* root, int sum) {
        if(root==NULL)
            return false;
        else if(sum == root->val&&root->left==NULL&&root->right==NULL)
            return true;
        bool tagleft=false;
        bool tagright=false;
        if(root->left!=NULL)
            tagleft = hasPathSum(root->left,sum-root->val);
        if(root->right!=NULL)
            tagright = hasPathSum(root->right,sum-root->val);
        
        if(tagleft||tagright)
            return true;
        
        return false;
        
    }
};