https://leetcode.com/problems/generate-parentheses/

Author: harshitgindra

LeetCodeSolutions/Backtracking/Generate Parentheses.cs

@@ -0,0 +1,61 @@
+using System.Text;
+
+namespace LeetCodeSolutions.Backtracking
+{
+    class GenerateParentheses
+    {
+        public IList<string> GenerateParenthesis(int n) {
+            List<string> result = new List<string>();
+            StringBuilder current = new StringBuilder();
+            Backtrack(result, current, 0, 0, n);
+            return result;
+        }
+
+        private void Backtrack(
+            List<string> result, 
+            StringBuilder current, 
+            int open, 
+            int close, 
+            int max
+        ) {
+            // Base case: valid combination complete
+            if (current.Length == max * 2) {
+                result.Add(current.ToString());
+                return;
+            }
+
+            // Add open parenthesis if we haven't reached the limit
+            if (open < max) {
+                current.Append('(');
+                Backtrack(result, current, open + 1, close, max);
+                current.Remove(current.Length - 1, 1); // Backtrack
+            }
+
+            // Add close parenthesis if it won't create imbalance
+            if (close < open) {
+                current.Append(')');
+                Backtrack(result, current, open, close + 1, max);
+                current.Remove(current.Length - 1, 1); // Backtrack
+            }
+        }
+
+        [Test(Description = "https://leetcode.com/problems/generate-parentheses/")]
+        [Category("Medium")]
+        [Category("LeetCode")]
+        [Category("Generate Parentheses")]
+        [TestCaseSource(nameof(Input))]
+        [Category("TopInterview")]
+        [Category("Backtracking")]
+        public void Test1((int Output, int Input) item)
+        {
+            var response = GenerateParenthesis(item.Input);
+            Assert.That(response.Count, Is.EqualTo(item.Output));
+        }
+
+        public static IEnumerable<(int Output, int Input)> Input =>
+            new List<(int Output, int Input)>()
+            {
+                (5, 3),
+            };
+    }
+}

README.md

@@ -163,7 +163,7 @@ The Top Interview 150 collection on Leetcode is a curated set of 150 interview q
 | 103                                          | Permutations                                                                                              | Medium     |   ✅     |
 | 104                                          | Combination Sum                                                                                           | Medium     |   ✅     |
 | 105                                          | N-Queens II                                                                                               | Hard       |  ✅      |
-| 106                                          | Generate Parentheses                                                                                      | Medium     |        |
+| 106                                          | Generate Parentheses                                                                                      | Medium     |   ✅     |
 | 107                                          | Word Search                                                                                               | Medium     |    ✅    |
 | <br>        Divide &amp; Conquer<br>         |                                                                                                           |            |        |
 | 108                                          | Convert Sorted Array to Binary Search Tree                                                                | Easy       |   ✅     |