diff --git a/a3/binary_search_tree.c b/a3/binary_search_tree.c
index 5a6ce53..c9db5d4 100644
--- a/a3/binary_search_tree.c
+++ b/a3/binary_search_tree.c
@@ -1,42 +1,34 @@
 #include "binary_search_tree.h"
 #include <stdlib.h>
 
+node_t *create_node(int data) {
+    node_t *node = (node_t *)malloc(sizeof(node_t));
+    node->data = data;
+    node->left = NULL;
+    node->right = NULL;
+    return node;
+}
+
+node_t *insert_node(node_t *tree, int data) {
+    if (tree == NULL) {
+        return create_node(data);
+    }
+
+    if (data < tree->data) {
+        tree->left = insert_node(tree->left, data);
+    } else if (data > tree->data) {
+        tree->right = insert_node(tree->right, data);
+    }
+
+    return tree;
+}
+
 node_t *build_tree(int *tree_data, size_t tree_data_len) {
-    if (tree_data_len == 0) {
-        return NULL;
+    node_t *tree = NULL;
+    for (size_t i = 0; i < tree_data_len; i++) {
+        tree = insert_node(tree, tree_data[i]);
     }
-
-    node_t *root = malloc(sizeof(node_t));
-    root->data = tree_data[0];
-    root->left = NULL;
-    root->right = NULL;
-
-    for (size_t i = 1; i < tree_data_len; i++) {
-        node_t *current = root;
-        node_t *parent = NULL;
-
-        while (current!= NULL) {
-            parent = current;
-            if (tree_data[i] < current->data) {
-                current = current->left;
-            } else {
-                current = current->right;
-            }
-        }
-
-        current = malloc(sizeof(node_t));
-        current->data = tree_data[i];
-        current->left = NULL;
-        current->right = NULL;
-
-        if (tree_data[i] < parent->data) {
-            parent->left = current;
-        } else {
-            parent->right = current;
-        }
-    }
-
-    return root;
+    return tree;
 }
 
 void free_tree(node_t *tree) {
@@ -49,25 +41,19 @@ void free_tree(node_t *tree) {
     free(tree);
 }
 
-int *sorted_data(node_t *tree) {
-    int *data = NULL;
-    size_t data_len = 0;
-
-    void in_order_traversal(node_t *node) {
-        if (node == NULL) {
-            return;
-        }
-
-        in_order_traversal(node->left);
-
-        data = realloc(data, (data_len + 1) * sizeof(int));
-        data[data_len] = node->data;
-        data_len++;
-
-        in_order_traversal(node->right);
+void in_order_traversal(node_t *tree, int *sorted_data, int *index) {
+    if (tree == NULL) {
+        return;
     }
 
-    in_order_traversal(tree);
+    in_order_traversal(tree->left, sorted_data, index);
+    sorted_data[(*index)++] = tree->data;
+    in_order_traversal(tree->right, sorted_data, index);
+}
 
-    return data;
+int *sorted_data(node_t *tree, size_t tree_data_len) {
+    int *sorted_data = (int *)malloc(tree_data_len * sizeof(int));
+    int index = 0;
+    in_order_traversal(tree, sorted_data, &index);
+    return sorted_data;
 }
\ No newline at end of file