feat: Add function to get DOM tree height recursively and iteratively

58.get-DOM-tree-height.md

@@ -0,0 +1,107 @@
+# 58. get DOM tree height
+
+### Problem
+
+https://bigfrontend.dev/problem/get-DOM-tree-height
+
+#
+
+### Problem Description
+
+Height of a tree is the maximum depth from root node. Empty root node have a height of 0.
+
+If given DOM tree, can you create a function to get the height of it?
+
+For the DOM tree below, we have a height of 4.
+
+```html
+<div>
+  <div>
+    <p>
+      <button>Hello</button>
+    </p>
+  </div>
+  <p>
+    <span>World!</span>
+  </p>
+</div>
+```
+
+Can you solve this both recursively and iteratively?
+
+#
+
+### Recursive Solution with DFS
+
+```js
+/**
+ * @param {HTMLElement | null} tree
+ * @return {number}
+ */
+function getHeight(tree) {
+  if (tree === null) {
+    return 0;
+  }
+  return 1 + Math.max(getTreeHeight(tree.left), getTreeHeight(tree.right));
+}
+```
+
+#
+
+### Iterative Solution using Stack
+
+```js
+/**
+ * @param {HTMLElement | null} tree
+ * @return {number}
+ */
+function getHeight(tree) {
+  if (tree === null) {
+    return 0;
+  }
+
+  let maxHeight = 0;
+  const stack = [[tree, 1]];
+
+  while (stack.length > 0) {
+    const [el, height] = stack.pop();
+    maxHeight = Math.max(height, maxHeight);
+
+    for (const child of el.children) {
+      stack.push([child, height + 1]);
+    }
+  }
+
+  return maxHeight;
+}
+```
+
+#
+
+### Iterative Solution with BFS
+
+```js
+/**
+ * @param {HTMLElement | null} tree
+ * @return {number}
+ */
+function getHeight(tree) {
+  if (tree === null) {
+    return 0;
+  }
+
+  let maxHeight = 0;
+  const queue = [[tree, 1]];
+
+  while (queue.length > 0) {
+    const [el, height] = queue.shift();
+    maxHeight = Math.max(height, maxHeight);
+
+    for (const child of el.children) {
+      queue.push([child, height + 1]);
+    }
+  }
+
+  return maxHeight;
+}
+```