feat: add solutions to lc problem: No.0921 (doocs#3628)

Author: rain84

solution/0900-0999/0921.Minimum Add to Make Parentheses Valid/README.md

@@ -286,4 +286,39 @@ function minAddToMakeValid(s: string): number {
 
 <!-- solution:end -->
 
+<!-- solution:start -->
+
+### 方法三：替换 + 递归
+
+<!-- tabs:start -->
+
+#### TypeScript
+
+```ts
+function minAddToMakeValid(s: string): number {
+    const l = s.length;
+    s = s.replace('()', '');
+
+    return s.length === l ? l : minAddToMakeValid(s);
+}
+```
+
+#### JavaScript
+
+```js
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var minAddToMakeValid = function (s) {
+    const l = s.length;
+    s = s.replace('()', '');
+    return s.length === l ? l : minAddToMakeValid(s);
+};
+```
+
+<!-- tabs:end -->
+
+<!-- solution:end -->
+
 <!-- problem:end -->

solution/0900-0999/0921.Minimum Add to Make Parentheses Valid/README_EN.md

@@ -284,4 +284,39 @@ function minAddToMakeValid(s: string): number {
 
 <!-- solution:end -->
 
+<!-- solution:start -->
+
+### Solution 3: Replace + recursion
+
+<!-- tabs:start -->
+
+#### TypeScript
+
+```ts
+function minAddToMakeValid(s: string): number {
+    const l = s.length;
+    s = s.replace('()', '');
+
+    return s.length === l ? l : minAddToMakeValid(s);
+}
+```
+
+#### JavaScript
+
+```js
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var minAddToMakeValid = function (s) {
+    const l = s.length;
+    s = s.replace('()', '');
+    return s.length === l ? l : minAddToMakeValid(s);
+};
+```
+
+<!-- tabs:end -->
+
+<!-- solution:end -->
+
 <!-- problem:end -->

solution/0900-0999/0921.Minimum Add to Make Parentheses Valid/Solution3.js

@@ -0,0 +1,9 @@
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var minAddToMakeValid = function (s) {
+    const l = s.length;
+    s = s.replace('()', '');
+    return s.length === l ? l : minAddToMakeValid(s);
+};

solution/0900-0999/0921.Minimum Add to Make Parentheses Valid/Solution3.ts

@@ -0,0 +1,6 @@
+function minAddToMakeValid(s: string): number {
+    const l = s.length;
+    s = s.replace('()', '');
+
+    return s.length === l ? l : minAddToMakeValid(s);
+}