construct a linked list from 2d matrix in c

C program for construct a linked list from 2d matrix. Here problem description and other solutions.

// C Program for
// Construct a linked list from 2D matrix
#include <stdio.h>

#include <stdlib.h> //for malloc function

#define ROW 3
#define COLS 5
//create structure
struct Node {
	int data;
	struct Node * next;
	struct Node * down;
};
// insert Node element of end of linked list
struct Node * insert(int value) {
	// Create a dynamic node
	struct Node * node = (struct Node * ) malloc(sizeof(struct Node));
	if (node == NULL) {
		printf("Memory overflow\n");
		exit(0);
	} else {
		//set data value
		node->data = value;
		node->next = NULL;
		node->down = NULL;
	}
	return node;
}
//display element of Node
void display(struct Node * head) {
	if (head == NULL) {
		printf("Empty linked list");
	} else {
		struct Node * right_side = NULL;
		//Traverse doubly linked list from front to rear
		while (head != NULL) {
			right_side = head;
			while (right_side != NULL) {
				printf("%3d", right_side->data);
				right_side = right_side->next;
			}
			printf("\n");
			head = head->down;
		}
	}
}
struct Node * insertData(int(*matrix)[COLS], 
                         int row, 
                         int cols) {
	struct Node *head = NULL, 
                *levelHead = NULL, 
                *root = NULL,
                *perv = NULL;
	// Add first rows in linked List
	for (int i = 0; i < cols; ++i) {
		if (head == NULL) {
			head = insert(matrix[0][i]);
			levelHead = head;
		} else {
			levelHead->next = insert(matrix[0][i]);
			levelHead = levelHead->next;
		}
	}
	levelHead = head;
	for (int i = 1; i < row; ++i) {
		root = NULL;
		perv = root;
		for (int j = 0; j < cols; ++j) {
			// Add element into next nows
			levelHead->down = insert(matrix[i][j]);
			if (root == NULL) {
				root = levelHead->down;
				perv = root;
			} else {
				perv->next = levelHead->down;
				perv = levelHead->down;
			}
			levelHead = levelHead->next;
		}
		levelHead = root;
	}
	return head;
}
int main() {
	// Create 2D metrix
	int matrix[ROW][COLS] = {
      {1,6,9,2,-9},
      {2,5,-5,7,1},
      {3,4,-1,8,2}
    };
	
	struct Node * head = insertData(matrix, ROW, COLS);
	display(head);
	return 0;
}

Output

  1  6  9  2 -9
  2  5 -5  7  1
  3  4 -1  8  2