112. Path Sum

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool check(TreeNode* root, int targetSum)
    {
        
        if(root==NULL && targetSum==0)
            return true;
        else if(root==NULL)
            return false;
        targetSum-=root->val;
        if(root->left==NULL)
            return check(root->right,targetSum);
        else if(root->right==NULL)
            return check(root->left,targetSum);
        return(check(root->left,targetSum) || check(root->right,targetSum));
    }
    bool hasPathSum(TreeNode* root, int targetSum) 
    {
        if(root==NULL)
            return false;
        return check(root,targetSum);
    }
};