solve inorder tree traversal by stack alternative

pallabez · Sep 13, 2023 · 67fb925 · 67fb925
1 parent b23cd4a
commit 67fb925
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diff --git a/Binary Search Tree/inorder_tree_walk.js b/Binary Search Tree/inorder_tree_walk.js
@@ -33,7 +33,27 @@ function inorderTreeWalkByStack(root) {
  }
 }
 
+function inorderTreeWalkByStackAlternative(root) {
+ if (root == null) return;
+
+ let stack = [];
+ let curr = root;
+
+ while (curr != null || stack.length != 0) {
+ while (curr != null) {
+ stack.push(curr);
+ curr = curr.left;
+ }
+
+ curr = stack.pop();
+ console.log(curr.element);
+
+ curr = curr.right;
+ }
+}
+
 module.exports = {
  inorderTreeWalkByRecursion,
- inorderTreeWalkByStack
+ inorderTreeWalkByStack,
+ inorderTreeWalkByStackAlternative
 }
diff --git a/Binary Search Tree/inorder_tree_walk.test.js b/Binary Search Tree/inorder_tree_walk.test.js
@@ -1,4 +1,4 @@
-const { inorderTreeWalkByRecursion, inorderTreeWalkByStack } = require('./inorder_tree_walk');
+const { inorderTreeWalkByRecursion, inorderTreeWalkByStack, inorderTreeWalkByStackAlternative } = require('./inorder_tree_walk');
 const { BinarySearchTree } = require('./BST');
 
 describe('Inorder Tree Walk', () => {
@@ -47,4 +47,27 @@ describe('Inorder Tree Walk', () => {
  expect(consoleLogSpy).toHaveBeenNthCalledWith(3, 3);
  })
  })
+
+ describe('By Stack alternative', () => {
+ it('should print null', () => {
+ inorderTreeWalkByStackAlternative(bst.root);
+ })
+
+ it('should print out element using console', () => {
+ bst.add(2);
+ bst.add(3);
+ bst.add(1);
+ bst.add(4);
+ bst.add(5);
+ bst.add(6);
+
+ inorderTreeWalkByStackAlternative(bst.root);
+ expect(consoleLogSpy).toHaveBeenNthCalledWith(1, 1);
+ expect(consoleLogSpy).toHaveBeenNthCalledWith(2, 2);
+ expect(consoleLogSpy).toHaveBeenNthCalledWith(3, 3);
+ expect(consoleLogSpy).toHaveBeenNthCalledWith(4, 4);
+ expect(consoleLogSpy).toHaveBeenNthCalledWith(5, 5);
+ expect(consoleLogSpy).toHaveBeenNthCalledWith(6, 6);
+ })
+ })
 });