datatypes: fixed v code style

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

vlib/datatypes/bstree.v

@@ -250,13 +250,13 @@ fn (bst &BSTree<T>) get_node(node &BSTreeNode<T>, value T) &BSTreeNode<T> {
 //```v
 // left_value, exist := bst.to_left(10)
 //```
-pub fn (bst &BSTree<T>) to_left(value T) (T, bool) {
+pub fn (bst &BSTree<T>) to_left(value T) ?T {
 	node := bst.get_node(bst.root, value)
 	if !node.is_init {
-		return node.value, false
+		return none
 	}
 	left_node := node.left
-	return left_node.value, left_node.is_init
+	return left_node.value
 }
 
 // to_right return the value of the element to the right of the node with `value` specified, if exist
@@ -266,25 +266,31 @@ pub fn (bst &BSTree<T>) to_left(value T) (T, bool) {
 //```v
 // left_value, exist := bst.to_right(10)
 //```
-pub fn (bst &BSTree<T>) to_right(value T) (T, bool) {
+pub fn (bst &BSTree<T>) to_right(value T) ?T {
 	node := bst.get_node(bst.root, value)
 	if !node.is_init {
-		return node.value, false
+		return none
 	}
 	right_node := node.right
-	return right_node.value, right_node.is_init
+	return right_node.value
 }
 
 // max return the max element inside the BST.
 // Time complexity O(N) if the BST is not balanced
-pub fn (bst &BSTree<T>) max() (T, bool) {
+pub fn (bst &BSTree<T>) max() ?T {
 	max := bst.get_max_from_right(bst.root)
-	return max.value, max.is_init
+	if !max.is_init {
+		return none
+	}
+	return max.value
 }
 
 // min return the minimum element in the BST.
 // Time complexity O(N) if the BST is not balanced.
-pub fn (bst &BSTree<T>) min() (T, bool) {
+pub fn (bst &BSTree<T>) min() ?T {
 	min := bst.get_min_from_left(bst.root)
-	return min.value, min.is_init
+	if !min.is_init {
+		return none
+	}
+	return min.value
 }

vlib/datatypes/bstree_test.v

@@ -67,12 +67,10 @@ fn test_get_left_root() {
 	assert bst.insert(21)
 	assert bst.insert(1)
 
-	left_val, found_left := bst.to_left(10)
-	assert found_left
+	left_val := bst.to_left(10) or { -1 }
 	assert left_val == 1
 
-	right_val, found_right := bst.to_right(10)
-	assert found_right
+	right_val := bst.to_right(10) or { -1 }
 	assert right_val == 20
 }
 
@@ -80,11 +78,11 @@ fn test_get_left_root() {
 fn test_get_left_on_empty_bst() {
 	mut bst := BSTree<int>{}
 
-	left_val, found_left := bst.to_left(10)
-	assert found_left == false
+	left_val := bst.to_left(10) or { -1 }
+	assert left_val == -1
 
-	right_val, found_right := bst.to_right(10)
-	assert found_right == false
+	right_val := bst.to_right(10) or { -1 }
+	assert right_val == -1
 }
 
 // Check the remove operation if it is able to remove
@@ -122,8 +120,7 @@ fn test_get_max_in_bst() {
 	assert bst.insert(20)
 	assert bst.insert(21)
 	assert bst.insert(1)
-	max, found := bst.max()
-	assert found
+	max := bst.max() or { -1 }
 	assert max == 21
 }
 
@@ -134,7 +131,6 @@ fn test_get_min_in_bst() {
 	assert bst.insert(20)
 	assert bst.insert(21)
 	assert bst.insert(1)
-	min, found := bst.min()
-	assert found
+	min := bst.min() or { -1 }
 	assert min == 1
 }