diff --git a/__tests__/structures/Tree.spec.ts b/__tests__/structures/Tree.spec.ts
index 2d6452f..428bac9 100644
--- a/__tests__/structures/Tree.spec.ts
+++ b/__tests__/structures/Tree.spec.ts
@@ -137,10 +137,10 @@ describe('Tree', () => {
     treeInsertChild(n1, n3)
     treeInsertChild(n1, n4)
 
-    expect(treeIsFirstChild(n2, n1)).toBeFalsy()
-    expect(treeIsFirstChild(n3, n1)).toBeFalsy()
-    expect(treeIsFirstChild(n4, n1)).toBeTruthy()
-    expect(treeIsLastChild(n2, n1)).toBeTruthy()
+    expect(treeIsFirstChild(n1, n2)).toBeFalsy()
+    expect(treeIsFirstChild(n1, n3)).toBeFalsy()
+    expect(treeIsFirstChild(n1, n4)).toBeTruthy()
+    expect(treeIsLastChild(n1, n2)).toBeTruthy()
     expect(n1.size).toBe(4)
   })
 
@@ -151,17 +151,17 @@ describe('Tree', () => {
     const n4 = createTreeNode(4, 'd')
 
     treeAppendChild(n1, n2)
-    expect(treeIsOnlyChild(n2, n1)).toBeTruthy()
+    expect(treeIsOnlyChild(n1, n2)).toBeTruthy()
 
     treeAppendChild(n1, n3)
-    expect(treeIsOnlyChild(n2, n1)).toBeFalsy()
+    expect(treeIsOnlyChild(n1, n2)).toBeFalsy()
 
     treeAppendChild(n1, n4)
 
-    expect(treeIsLastChild(n2, n1)).toBeFalsy()
-    expect(treeIsLastChild(n3, n1)).toBeFalsy()
-    expect(treeIsLastChild(n4, n1)).toBeTruthy()
-    expect(treeIsFirstChild(n2, n1)).toBeTruthy()
+    expect(treeIsLastChild(n1, n2)).toBeFalsy()
+    expect(treeIsLastChild(n1, n3)).toBeFalsy()
+    expect(treeIsLastChild(n1, n4)).toBeTruthy()
+    expect(treeIsFirstChild(n1, n2)).toBeTruthy()
     expect(n1.size).toBe(4)
   })
 
@@ -227,10 +227,10 @@ describe('Tree', () => {
     const n7 = createTreeNode(7, 'g')
 
     treeInsertChild(n1, n2)
-    expect(treeIsOnlyChild(n2, n1)).toBeTruthy()
+    expect(treeIsOnlyChild(n1, n2)).toBeTruthy()
 
     treeInsertChild(n1, n3)
-    expect(treeIsOnlyChild(n3, n1)).toBeFalsy()
+    expect(treeIsOnlyChild(n1, n3)).toBeFalsy()
 
     treeInsertChild(n1, n4)
     treeInsertChild(n1, n5)
diff --git a/package-lock.json b/package-lock.json
index 026b6aa..3d720be 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@cosmicmind/algojs",
-  "version": "0.0.1-rc-102823-2-c",
+  "version": "0.0.1-rc-102823-2-d",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@cosmicmind/algojs",
-      "version": "0.0.1-rc-102823-2-c",
+      "version": "0.0.1-rc-102823-2-d",
       "license": "BSD-3-Clause",
       "dependencies": {
         "@cosmicmind/foundationjs": "^0.0.1-rc-092723-1"
diff --git a/package.json b/package.json
index 5b6a0d0..e50f722 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@cosmicmind/algojs",
-  "version": "0.0.1-rc-102823-2-c",
+  "version": "0.0.1-rc-102823-2-d",
   "description": "An algorithms and data structures library in TypeScript.",
   "keywords": [],
   "author": {
diff --git a/src/structures/Tree.ts b/src/structures/Tree.ts
index 5195d28..c7c52b9 100644
--- a/src/structures/Tree.ts
+++ b/src/structures/Tree.ts
@@ -155,21 +155,21 @@ export function treeIsChild<T extends Tree>(parent: T, node: T, compare = TreeCo
 /**
  * @performance O(1)
  */
-export function treeIsFirstChild<T extends Tree>(node: T, parent: T, compare = TreeCompareFn<T>): boolean {
+export function treeIsFirstChild<T extends Tree>(parent: T, node: T, compare = TreeCompareFn<T>): boolean {
   return listIsFirst(parent.children as List<T>, node, compare)
 }
 
 /**
  * @performance O(1)
  */
-export function treeIsLastChild<T extends Tree>(node: T, parent: T, compare = TreeCompareFn<T>): boolean {
+export function treeIsLastChild<T extends Tree>(parent: T, node: T, compare = TreeCompareFn<T>): boolean {
   return listIsLast(parent.children as List<T>, node, compare)
 }
 
 /**
  * @performance O(1)
  */
-export function treeIsOnlyChild<T extends Tree>(node: T, parent: T, compare = TreeCompareFn<T>): boolean {
+export function treeIsOnlyChild<T extends Tree>(parent: T, node: T, compare = TreeCompareFn<T>): boolean {
   return listIsFirst(parent.children as List<T>, node, compare) && listIsLast(parent.children as List<T>, node, compare)
 }