Add solution #1110

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,139 LeetCode solutions in JavaScript
+# 1,140 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -883,6 +883,7 @@
 1106|[Parsing A Boolean Expression](./solutions/1106-parsing-a-boolean-expression.js)|Hard|
 1108|[Defanging an IP Address](./solutions/1108-defanging-an-ip-address.js)|Easy|
 1109|[Corporate Flight Bookings](./solutions/1109-corporate-flight-bookings.js)|Medium|
+1110|[Delete Nodes And Return Forest](./solutions/1110-delete-nodes-and-return-forest.js)|Medium|
 1122|[Relative Sort Array](./solutions/1122-relative-sort-array.js)|Easy|
 1123|[Lowest Common Ancestor of Deepest Leaves](./solutions/1123-lowest-common-ancestor-of-deepest-leaves.js)|Medium|
 1137|[N-th Tribonacci Number](./solutions/1137-n-th-tribonacci-number.js)|Easy|

solutions/1110-delete-nodes-and-return-forest.js

@@ -0,0 +1,45 @@
+/**
+ * 1110. Delete Nodes And Return Forest
+ * https://leetcode.com/problems/delete-nodes-and-return-forest/
+ * Difficulty: Medium
+ *
+ * Given the root of a binary tree, each node in the tree has a distinct value.
+ *
+ * After deleting all nodes with a value in toDelete, we are left with a forest (a disjoint
+ * union of trees).
+ *
+ * Return the roots of the trees in the remaining forest. You may return the result in any order.
+ */
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @param {number[]} toDelete
+ * @return {TreeNode[]}
+ */
+var delNodes = function(root, toDelete) {
+  const deleteSet = new Set(toDelete);
+  const forest = [];
+
+  traverse(root, true);
+  return forest;
+
+  function traverse(node, isRoot) {
+    if (!node) return null;
+
+    const shouldDelete = deleteSet.has(node.val);
+    if (isRoot && !shouldDelete) forest.push(node);
+
+    node.left = traverse(node.left, shouldDelete);
+    node.right = traverse(node.right, shouldDelete);
+
+    return shouldDelete ? null : node;
+  }
+};