Add solution #1021

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,401 LeetCode solutions in JavaScript
+# 1,402 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -837,6 +837,7 @@
 1018|[Binary Prefix Divisible By 5](./solutions/1018-binary-prefix-divisible-by-5.js)|Easy|
 1019|[Next Greater Node In Linked List](./solutions/1019-next-greater-node-in-linked-list.js)|Medium|
 1020|[Number of Enclaves](./solutions/1020-number-of-enclaves.js)|Medium|
+1021|[Remove Outermost Parentheses](./solutions/1021-remove-outermost-parentheses.js)|Easy|
 1022|[Sum of Root To Leaf Binary Numbers](./solutions/1022-sum-of-root-to-leaf-binary-numbers.js)|Easy|
 1023|[Camelcase Matching](./solutions/1023-camelcase-matching.js)|Medium|
 1024|[Video Stitching](./solutions/1024-video-stitching.js)|Medium|

solutions/1021-remove-outermost-parentheses.js

@@ -0,0 +1,39 @@
+/**
+ * 1021. Remove Outermost Parentheses
+ * https://leetcode.com/problems/remove-outermost-parentheses/
+ * Difficulty: Easy
+ *
+ * A valid parentheses string is either empty "", "(" + A + ")", or A + B, where A and B are valid
+ * parentheses strings, and + represents string concatenation.
+ * - For example, "", "()", "(())()", and "(()(()))" are all valid parentheses strings.
+ *
+ * A valid parentheses string s is primitive if it is nonempty, and there does not exist a way to
+ * split it into s = A + B, with A and B nonempty valid parentheses strings.
+ *
+ * Given a valid parentheses string s, consider its primitive decomposition: s = P1
+ * + P2 + ... + Pk, where Pi are primitive valid parentheses strings.
+ *
+ * Return s after removing the outermost parentheses of every primitive string in the primitive
+ * decomposition of s.
+ */
+
+/**
+ * @param {string} s
+ * @return {string}
+ */
+var removeOuterParentheses = function(s) {
+  let result = '';
+  let depth = 0;
+
+  for (const char of s) {
+    if (char === '(') {
+      if (depth > 0) result += char;
+      depth++;
+    } else {
+      depth--;
+      if (depth > 0) result += char;
+    }
+  }
+
+  return result;
+};