Count Nodes Equal to Average of Subtree

class Solution {
public:
    int count = 0;

    pair<int, int> postOrder(TreeNode* root) {
        if (root == NULL) {
            return {0, 0};
        }

        // First iterate over left and right subtrees.
        pair<int, int> left = postOrder(root->left);
        pair<int, int> right = postOrder(root->right);

        int nodeSum = left.first + right.first + root->val;
        int nodeCount = left.second + right.second + 1;

        // Check if the average of the subtree is equal to the node value.
        if (root->val == nodeSum / (nodeCount)) {
            count++;
        }

        // Return the sum of nodes and the count in the subtree.
        return {nodeSum, nodeCount};
    }

    int averageOfSubtree(TreeNode* root) {
        postOrder(root);
        return count;
    }
};