Small C program that constructs a Cartesian tree from an array (and generates a Graphviz dot file from it)

CartesianTree.c

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

struct Node{
    struct Node *parent;
    struct Node *left;
    struct Node *right;
    int index;
    int value;
};

typedef struct Node Node;

Node* createNode(Node* parent, Node* left, Node* right, int index, int value){
    Node* node = malloc(sizeof(Node));
    if (node == NULL)
        printf("[Error] malloc returned NULL");

    node->parent = parent;
    node->left = left;
    node->right = right;

    node->index = index;
    node->value = value;

    return node;
}

Node* buildCartesianTree(int arr[], int len){
    Node* cur = NULL;

    for(int i = 0; i < len; i++){
        Node* node = createNode(NULL, NULL, NULL, i, arr[i]);

        
        if (cur == NULL){
            cur = node;
            continue;
        }

        //printf("(%d, %d)\n", cur->value, node->value);


        if (cur->value < node->value){
            cur->right = node;
            node->parent = cur;
            cur = node;
        } else {
            while (cur->value >= node->value){
                if (cur->parent == NULL){
                    break;
                }
                cur = cur->parent;
            }

            if (cur->value >= node->value){
                cur->parent = node;
                node->left = cur;
                cur = node;

            } else {
                node->parent = cur;
                node->left = cur->right;
                cur->right = node;
                
                if(cur->right != NULL){
                    node->left->parent = node;
                }
                cur = node;
            }
        }
    }

    while(cur->parent != NULL){
        cur = cur->parent;
    }

    return cur;
}

void printNode(Node* node, int depth){

    if (node->left != NULL){
        printNode(node->left, depth+1);
    }


    for(int i = 0; i < depth; i++){
        printf(" ");
    }
    printf("[%d] %d\n", node->index, node->value);

    

    if (node->right != NULL){
        printNode(node->right, depth+1);
    }
}

void print(Node* root){
    printNode(root, 0);
}

void printDotNode(Node* node){
    //printf("\t%d [label=\"%d @ [%d]\"];\n", node->index, node->value, node->index);

    if (node->left != NULL){
        printf("\t%d -> %d;\n", node->value, node->left->value);
        printDotNode(node->left);
    }

    if (node->right != NULL){
        printf("\t%d -> %d;\n", node->value, node->right->value);
        printDotNode(node->right);
    }
}

void printDot(Node* root){
    printf("digraph G{\n");

    printDotNode(root);

    printf("}\n");
}

int main(){
    int arr[] = {4, 5, 7, 3, 8, 9, 2, 6, 1, 0};

    //int arr[] = {7, 8, 9, 10, 4, 12, 6, 11, 5, 3, 1, 2};

    int len = sizeof(arr)/sizeof(int);

    //printf("\\\\%d\n", len);

    Node * root = buildCartesianTree(arr, len);
    
    printDot(root);
    //printf("hello world!\n");
}