Help me in solving BTPREORDER problem

help
,
1

My issue

run time error prob
lem in code how to solve

My code

#include <stdio.h>
#include <stdlib.h>


typedef struct Solution {
    void (*preOrderTraversal)(Node* root);
} Solution;

// Function to perform pre-order traversal
void preOrderTraversal(Node* root) {
    if (root == NULL) {
        return;  // Base case: if the node is NULL, do nothing
    }
    
    printf("%d ", root->val);  // Visit the current node (print its value)
    
    // Traverse the left subtree
    preOrderTraversal(root->left);
    
    // Traverse the right subtree
    preOrderTraversal(root->right);
}

// Function to create a new Solution object and return it
Solution* createSolution() {
    Solution* sol = (Solution*)malloc(sizeof(Solution));  // Allocate memory for Solution
    sol->preOrderTraversal = preOrderTraversal;  // Assign the function pointer
    return sol;
}

Learning course: BCS301: Data structures
Problem Link: https://www.codechef.com/learn/course/abesit-dsa/ABESITDS29/problems/BTPREORDER