https://leetcode.com/problems/3sum/

Author: harshitgindra

LeetCodeSolutions/TwoPointers/ThreeSum.cs

@@ -0,0 +1,68 @@
+namespace LeetCodeSolutions.TwoPointers
+{
+    public class ThreeSumSolution
+    {
+        public IList<IList<int>> ThreeSum(int[] nums)
+        {
+            IList<IList<int>> returnValue = new List<IList<int>>();
+            Array.Sort(nums);
+
+            for (int i = 0; i < nums.Length; i++)
+            {
+                if (i > 0 && nums[i] == nums[i - 1])
+                    continue;
+
+                int left = i + 1;
+                int right = nums.Length - 1;
+
+                while (left < right)
+                {
+                    int threeSum = nums[i] + nums[left] + nums[right];
+
+                    if (threeSum > 0)
+                        right--;
+                    else if (threeSum < 0)
+                        left++;
+                    else
+                    {
+                        List<int> currentList =
+                        [
+                            nums[i],
+                            nums[left],
+                            nums[right]
+                        ];
+                        returnValue.Add(currentList);
+                        left++;
+                        while (nums[left] == nums[left - 1] && left < right)
+                            left++;
+                    }
+                }
+            }
+
+            return returnValue;
+        }
+
+        [Test(Description = "https://leetcode.com/problems/3sum/")]
+        [Category("Medium")]
+        [Category("LeetCode")]
+        [Category("3Sum")]
+        [TestCaseSource(nameof(Input))]
+        [Category("TwoPointers")]
+        [Category("TopInterview")]
+        public void Test1((IList<IList<int>> Output, int[] Input) item)
+        {
+            var response = ThreeSum(item.Input);
+            Assert.That(response, Is.EqualTo(item.Output));
+        }
+
+        public static IEnumerable<(IList<IList<int>> Output, int[] Input)> Input =>
+            new List<(IList<IList<int>> Output, int[] Input)>()
+            {
+                (new List<IList<int>>()
+                {
+                    new List<int>() { -1, -1, 2 },
+                    new List<int>() { -1, 0, 1 }
+                }, [-1, 0, 1, 2, -1, -4]),
+            };
+    }
+}

README.md

@@ -73,7 +73,7 @@ The Top Interview 150 collection on Leetcode is a curated set of 150 interview q
 | 26                                           |  Is Subsequence                                          | Easy       |   ✅     |
 | 27                                           |  Two Sum II - Input Array Is Sorted                      | Medium     |   ✅     |
 | 28                                           |  Container With Most Water                               | Medium     |   ✅     |
-| 29                                           |  3Sum                                                    | Medium     |        |
+| 29                                           |  3Sum                                                    | Medium     |   ✅     |
 | <br>        Sliding Window<br>               |                                                                                                           |            |        |
 | 30                                           |  Minimum Size Subarray Sum                               | Medium     |        |
 | 31                                           |  Longest Substring Without Repeating Characters          | Medium     |        |