Create 22. Generate Parentheses.md

Author: TBXark

22. Generate Parentheses.md

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+# 22. Generate Parentheses
+
+### 2022-05-09
+
+Given `n` pairs of parentheses, write a function to generate all combinations of well-formed parentheses.
+
+ 
+
+Example 1:
+```
+Input: n = 3
+Output: ["((()))","(()())","(())()","()(())","()()()"]
+```
+
+Example 2:
+```
+Input: n = 1
+Output: ["()"]
+```
+
+
+
+# Solution
+
+```swift
+class Solution {
+    
+    private func generateParenthesis(left: Int, right: Int, max: Int, str: String, result: inout [String])  {
+        if left == max, right == max {
+            result.append(str)
+            return
+        }
+        if left < max {
+            generateParenthesis(left: left + 1, right: right, max: max, str: str + "(", result: &result)
+        }
+        if left > right {
+            generateParenthesis(left: left, right: right + 1, max: max, str: str + ")", result: &result)
+        }
+    }
+    
+    func generateParenthesis(_ n: Int) -> [String] {
+        var temp = [String]()
+        generateParenthesis(left: 0, right: 0, max: n, str: "", result: &temp)
+        return temp
+    }
+}
+
+```