Leetcode:Path Sum in C++

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.

For example:
Given the below binary tree and sum = 22,

              5
             / \
            4   8
           /   / \
          11  13  4
         /  \      \
        7    2      1

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

Solution:

bool hasPathSum(TreeNode *root, int sum) {
        if(!root)
            return false;
        if(sum - root->val==0&&!root->left&&!root->right)
            return true;
        bool left = false;
        bool right =false;
        if(root->left)
            left = hasPathSum(root->left, sum - root->val);
        if(root->right)
            right = hasPathSum(root->right, sum - root->val);
        return left||right;
    }