add 230-Kth-Smallest-Element-in-a-BST

javascript/230-Kth-Smallest-Element-in-a-BST.js

@@ -0,0 +1,21 @@
+function kthSmallest(root, k) {
+  let n = 0;
+  const stack = [];
+  let cur = root;
+
+  while (cur || stack) {
+    while (cur) {
+      stack.push(cur);
+      cur = cur.left;
+    }
+
+    cur = stack.pop();
+    n += 1;
+
+    if (n == k) {
+      return cur.val;
+    }
+
+    cur = cur?.right;
+  }
+}