Path sum

class Solution {
public:

    bool f(TreeNode* root, int targetSum){

        if(root==NULL)return false;

        if(root->left==NULL && root->right==NULL && targetSum == root->val){
            return true;
        }

        if(f(root->left,targetSum-root->val)==true || f(root->right,targetSum-root->val)==true)return true;

        return false;

    }

    bool hasPathSum(TreeNode* root, int targetSum) {

        return f(root,targetSum);

    }
};