change trees and list data to int

epi/bst_to_sorted_list/solution_test.go

@@ -67,7 +67,7 @@ func bstToDoublyLinkedListWrapper(t *tree.BSTNode) ([]int, error) {
 
 	v := make([]int, 0)
 	for list != nil {
-		v = append(v, list.Data.(int))
+		v = append(v, list.Data)
 		if list.Right != nil && list.Right.Left != list {
 			return nil, errors.New("list is ill-formed")
 		}

epi/do_lists_overlap/solution_test.go

@@ -119,11 +119,11 @@ func overlappingListsWrapper(l0 *list.Node, l1 *list.Node, common *list.Node, cy
 
 	commonNodes := make(map[int]bool)
 	for it := common; it != nil; it = it.Next {
-		if _, ok := commonNodes[it.Data.(int)]; ok {
+		if _, ok := commonNodes[it.Data]; ok {
 			break
 		}
 
-		commonNodes[it.Data.(int)] = true
+		commonNodes[it.Data] = true
 	}
 
 	result := OverlappingLists(l0, l1)
@@ -137,7 +137,7 @@ func overlappingListsWrapper(l0 *list.Node, l1 *list.Node, common *list.Node, cy
 			return errors.New("invalid result")
 		}
 
-		_, ok := commonNodes[result.Data.(int)]
+		_, ok := commonNodes[result.Data]
 		if !ok {
 			return errors.New("invalid result")
 		}

epi/is_list_cyclic/solution_test.go

@@ -63,7 +63,7 @@ func hasCycleWrapper(head *list.Node, cycleIdx int) error {
 		cursor := head
 
 		for cursor.Next != nil {
-			if cursor.Data.(int) == cycleIdx {
+			if cursor.Data == cycleIdx {
 				cycleStart = cursor
 			}
 			cursor = cursor.Next
@@ -84,7 +84,7 @@ func hasCycleWrapper(head *list.Node, cycleIdx int) error {
 
 	if cycleIdx == -1 {
 		if result != nil {
-			return fmt.Errorf("expected no cycle, got %d", result.Data.(int))
+			return fmt.Errorf("expected no cycle, got %d", result.Data)
 		}
 	} else {
 		if result == nil {

epi/kth_node_in_tree/solution_test.go

@@ -78,7 +78,7 @@ func convertToTreeWithSize(original *tree.BinaryTree) *BinaryTreeNode {
 	}
 
 	return &BinaryTreeNode{
-		Data:  original.Data.(int),
+		Data:  original.Data,
 		Left:  left,
 		Right: right,
 		Size:  1 + lSize + rSize,

epi/lowest_common_ancestor/solution_test.go

@@ -75,5 +75,5 @@ func lcaWrapper(inputTree *tree.BinaryTreeNode, key0 int, key1 int) (int, error)
 		return 0, errors.New("result can not be nil")
 	}
 
-	return result.Data.(int), nil
+	return result.Data, nil
 }

epi/lowest_common_ancestor_close_ancestor/solution_test.go

@@ -75,5 +75,5 @@ func lcaCloseWrapper(inputTree *tree.BinaryTree, key0 int, key1 int) (int, error
 		return 0, errors.New("result can not be nil")
 	}
 
-	return result.Data.(int), nil
+	return result.Data, nil
 }

epi/lowest_common_ancestor_in_bst/solution_test.go

@@ -75,5 +75,5 @@ func findLCAWrapper(inputTree *tree.BSTNode, key0 int, key1 int) (int, error) {
 		return 0, errors.New("result can not be nil")
 	}
 
-	return result.Data.(int), nil
+	return result.Data, nil
 }

epi/lowest_common_ancestor_with_parent/solution_test.go

@@ -75,5 +75,5 @@ func lcaWrapper(inputTree *tree.BinaryTree, key0 int, key1 int) (int, error) {
 		return 0, errors.New("result can not be nil")
 	}
 
-	return result.Data.(int), nil
+	return result.Data, nil
 }

epi/search_first_greater_value_in_bst/solution_test.go

@@ -64,7 +64,7 @@ func TestFindFirstGreaterThanK(t *testing.T) {
 
 func findFirstGreaterThanKWrapper(tree *tree.BSTNode, k int) (int, error) {
 	if result := FindFirstGreaterThanK(tree, k); result != nil {
-		return result.Data.(int), nil
+		return result.Data, nil
 	}
 	return -1, nil
 }

epi/search_in_bst/solution_test.go

@@ -61,7 +61,7 @@ func TestSearchBST(t *testing.T) {
 
 func searchBSTWrapper(tree *tree.BSTNode, key int) int {
 	if result := SearchBST(tree, key); result != nil {
-		return result.Data.(int)
+		return result.Data
 	}
 	return -1
 }

epi/search_in_list/solution_test.go

@@ -60,7 +60,7 @@ func TestSearchList(t *testing.T) {
 
 func searchListWrapper(l *list.Node, key int) int {
 	if result := SearchList(l, key); result != nil {
-		return result.Data.(int)
+		return result.Data
 	}
 
 	return -1

epi/sorted_list_to_bst/solution_test.go

@@ -89,7 +89,7 @@ func compareIterAndTree(tree *list.DoublyLinkedNode, it *iterator.Iterator) erro
 	next := it.Next()
 
 	if next != tree.Data {
-		return fmt.Errorf("expected value %d, got %d", next.(int), tree.Data.(int))
+		return fmt.Errorf("expected value %d, got %d", next.(int), tree.Data)
 	}
 
 	if err := compareIterAndTree(tree.Next, it); err != nil {

epi/successor_in_tree/solution_test.go

@@ -68,5 +68,5 @@ func findSuccessorWrapper(inputTree *tree.BinaryTree, nodeIdx int) int {
 		return -1
 	}
 
-	return result.Data.(int)
+	return result.Data
 }

epi/tree_connect_leaves/solution_test.go

@@ -64,14 +64,14 @@ func createListOfLeavesWrapper(tree *tree.BinaryTreeNode) ([]int, error) {
 	result := CreateListOfLeaves(tree)
 
 	for i, n := range result {
-		if n == nil || n.Data == nil {
+		if n == nil {
 			return nil, fmt.Errorf("result contains a nil node at index %d", i)
 		}
 	}
 
 	extractedRes := make([]int, len(result))
 	for i, n := range result {
-		extractedRes[i] = n.Data.(int)
+		extractedRes[i] = n.Data
 	}
 
 	return extractedRes, nil

epi/tree_exterior/solution_test.go

@@ -73,7 +73,7 @@ func createOutputList(l []*tree.BinaryTreeNode) ([]int, error) {
 		if t == nil {
 			return nil, errors.New("result list contains nil")
 		}
-		output = append(output, t.Data.(int))
+		output = append(output, t.Data)
 	}
 
 	return output, nil

epi/tree_right_sibling/binary_tree_node_with_next.go

@@ -1,7 +1,7 @@
 package tree_right_sibling
 
 type BinaryTreeNodeWithNext struct {
-	Data        interface{}
+	Data        int
 	Left, Right *BinaryTreeNodeWithNext
 	Next        *BinaryTreeNodeWithNext
 }

epi/tree_right_sibling/solution_test.go

@@ -68,7 +68,7 @@ func constructRightSiblingWrapper(tree *BinaryTreeNodeWithNext) [][]int {
 		level := make([]int, 0)
 		levelIter := levelStart
 		for levelIter != nil {
-			level = append(level, levelIter.Data.(int))
+			level = append(level, levelIter.Data)
 			levelIter = levelIter.Next
 		}
 		result = append(result, level)

list/doubly_linked_node.go

@@ -1,6 +1,6 @@
 package list
 
 type DoublyLinkedNode struct {
-	Data       interface{}
+	Data       int
 	Prev, Next *DoublyLinkedNode
 }

list/node.go

@@ -6,7 +6,7 @@ import (
 )
 
 type Node struct {
-	Data interface{}
+	Data int
 	Next *Node
 }
 

list/utils.go

@@ -10,7 +10,7 @@ func ToArray(l *Node) []int {
 			panic("cycle detected")
 		}
 		seenNodes[cursor] = true
-		result = append(result, cursor.Data.(int))
+		result = append(result, cursor.Data)
 	}
 	return result
 }
@@ -124,7 +124,7 @@ func DoublyLinkedNodeToSlice(l *DoublyLinkedNode) []int {
 			panic("cycle detected")
 		}
 		seenNodes[cursor] = true
-		result = append(result, cursor.Data.(int))
+		result = append(result, cursor.Data)
 	}
 	return result
 }

tree/binary_tree.go

@@ -1,7 +1,7 @@
 package tree
 
 type BinaryTree struct {
-	Data                interface{}
+	Data                int
 	Left, Right, Parent *BinaryTree
 }
 
@@ -13,7 +13,7 @@ func (b *BinaryTree) String() string {
 	return s
 }
 
-func (b BinaryTree) GetData() interface{} {
+func (b BinaryTree) GetData() int {
 	return b.Data
 }
 

tree/binary_tree_node.go

@@ -1,7 +1,7 @@
 package tree
 
 type BinaryTreeNode struct {
-	Data        interface{}
+	Data        int
 	Left, Right *BinaryTreeNode
 }
 
@@ -13,7 +13,7 @@ func (b *BinaryTreeNode) String() string {
 	return s
 }
 
-func (b BinaryTreeNode) GetData() interface{} {
+func (b BinaryTreeNode) GetData() int {
 	return b.Data
 }
 

tree/bst_node.go

@@ -1,7 +1,7 @@
 package tree
 
 type BSTNode struct {
-	Data        interface{}
+	Data        int
 	Left, Right *BSTNode
 }
 
@@ -13,7 +13,7 @@ func (b *BSTNode) String() string {
 	return s
 }
 
-func (b BSTNode) GetData() interface{} {
+func (b BSTNode) GetData() int {
 	return b.Data
 }
 

tree/utils.go

@@ -12,7 +12,7 @@ import (
 )
 
 type TreeLike interface {
-	GetData() interface{}
+	GetData() int
 	GetLeft() TreeLike
 	GetRight() TreeLike
 }
@@ -117,7 +117,7 @@ func GenerateInorder(tree TreeLike) []int {
 		if initial {
 			initial = false
 		} else {
-			result = append(result, treeNode.GetData().(int))
+			result = append(result, treeNode.GetData())
 			treeNode = treeNode.GetRight()
 		}
 
@@ -204,7 +204,7 @@ func AssertTreeIsBST(tree TreeLike) error {
 			continue
 		}
 
-		value := node.Tree.GetData().(int)
+		value := node.Tree.GetData()
 
 		if !node.Range.contains(value) {
 			return fmt.Errorf(