Add solution #1669

Author: JoshCrozier

1669-merge-in-between-linked-lists.js

@@ -0,0 +1,44 @@
+/**
+ * 1669. Merge In Between Linked Lists
+ * https://leetcode.com/problems/merge-in-between-linked-lists/
+ * Difficulty: Medium
+ *
+ * You are given two linked lists: list1 and list2 of sizes n and m respectively.
+ *
+ * Remove list1's nodes from the ath node to the bth node, and put list2 in their place.
+ *
+ * The blue edges and nodes in the following figure indicate the result:
+ */
+
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} list1
+ * @param {number} a
+ * @param {number} b
+ * @param {ListNode} list2
+ * @return {ListNode}
+ */
+var mergeInBetween = function(list1, a, b, list2) {
+  const result = new ListNode(0, list1);
+
+  for (let i = 1; i < a; i++) {
+    list1 = list1.next;
+  }
+  let tail = list1.next;
+  list1.next = list2;
+  for (let i = a; i < b; i++) {
+    tail = tail.next;
+  }
+  while (list1 && list1.next) {
+    list1 = list1.next;
+  }
+  list1.next = tail.next;
+
+  return result.next;
+};

README.md

@@ -239,6 +239,7 @@
 1566|[Detect Pattern of Length M Repeated K or More Times](./1566-detect-pattern-of-length-m-repeated-k-or-more-times.js)|Easy|
 1598|[Crawler Log Folder](./1598-crawler-log-folder.js)|Easy|
 1668|[Maximum Repeating Substring](./1668-maximum-repeating-substring.js)|Easy|
+1669|[Merge In Between Linked Lists](./1669-merge-in-between-linked-lists.js)|Medium|
 1672|[Richest Customer Wealth](./1672-richest-customer-wealth.js)|Easy|
 1748|[Sum of Unique Elements](./1748-sum-of-unique-elements.js)|Easy|
 1780|[Check if Number is a Sum of Powers of Three](./1780-check-if-number-is-a-sum-of-powers-of-three.js)|Medium|