Add solution #1370

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,258 LeetCode solutions in JavaScript
+# 1,259 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1042,6 +1042,7 @@
 1366|[Rank Teams by Votes](./solutions/1366-rank-teams-by-votes.js)|Medium|
 1367|[Linked List in Binary Tree](./solutions/1367-linked-list-in-binary-tree.js)|Medium|
 1368|[Minimum Cost to Make at Least One Valid Path in a Grid](./solutions/1368-minimum-cost-to-make-at-least-one-valid-path-in-a-grid.js)|Hard|
+1370|[Increasing Decreasing String](./solutions/1370-increasing-decreasing-string.js)|Easy|
 1372|[Longest ZigZag Path in a Binary Tree](./solutions/1372-longest-zigzag-path-in-a-binary-tree.js)|Medium|
 1374|[Generate a String With Characters That Have Odd Counts](./solutions/1374-generate-a-string-with-characters-that-have-odd-counts.js)|Easy|
 1380|[Lucky Numbers in a Matrix](./solutions/1380-lucky-numbers-in-a-matrix.js)|Easy|

solutions/1370-increasing-decreasing-string.js

@@ -0,0 +1,50 @@
+/**
+ * 1370. Increasing Decreasing String
+ * https://leetcode.com/problems/increasing-decreasing-string/
+ * Difficulty: Easy
+ *
+ * You are given a string s. Reorder the string using the following algorithm:
+ * 1. Remove the smallest character from s and append it to the result.
+ * 2. Remove the smallest character from s that is greater than the last appended character,
+ *   and append it to the result.
+ * 3. Repeat step 2 until no more characters can be removed.
+ * 4. Remove the largest character from s and append it to the result.
+ * 5. Remove the largest character from s that is smaller than the last appended character,
+ *   and append it to the result.
+ * 6. Repeat step 5 until no more characters can be removed.
+ * 7. Repeat steps 1 through 6 until all characters from s have been removed.
+ *
+ * If the smallest or largest character appears more than once, you may choose any occurrence to
+ * append to the result.
+ *
+ * Return the resulting string after reordering s using this algorithm.
+ */
+
+/**
+ * @param {string} s
+ * @return {string}
+ */
+var sortString = function(s) {
+  const charCounts = new Array(26).fill(0);
+  for (const char of s) {
+    charCounts[char.charCodeAt(0) - 97]++;
+  }
+
+  let result = '';
+  while (result.length < s.length) {
+    for (let i = 0; i < 26; i++) {
+      if (charCounts[i] > 0) {
+        result += String.fromCharCode(i + 97);
+        charCounts[i]--;
+      }
+    }
+    for (let i = 25; i >= 0; i--) {
+      if (charCounts[i] > 0) {
+        result += String.fromCharCode(i + 97);
+        charCounts[i]--;
+      }
+    }
+  }
+
+  return result;
+};