Sort Colors, 3Sum and Container With Most Water

Problem1.cs

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+// Time Complexity : O(n) where n is the total length of nums array
+// Space Complexity : O(1)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+public class Solution {
+    public void SortColors(int[] nums) {
+        int slow = 0, mid = 0, fast = nums.Length - 1;
+
+        while(mid <= fast)
+        {
+            if(nums[mid] == 2)
+            {
+                Swap(nums, mid, fast);
+                fast--;
+            }
+
+            else if(nums[mid] == 0)
+            {
+                Swap(nums, slow, mid);
+                slow++;
+                mid++;
+            }
+
+            else
+            {
+                mid++;
+            }
+        }
+    }
+
+    public void Swap(int[] nums, int i, int j)
+    {
+        int temp = nums[i];
+        nums[i] = nums[j];
+        nums[j] = temp;
+    }
+}

Problem2.cs

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+// Time Complexity : O(n) where n is the total length of nums array
+// Space Complexity : O(n)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+public class Solution {
+    public IList<IList<int>> ThreeSum(int[] nums) {
+        Array.Sort(nums);
+        List<IList<int>> result = new();
+        for(int i = 0; i < nums.Length - 2; i++)
+        {
+            if(i>0 && nums[i]==nums[i-1])
+            {
+                continue;
+            }
+
+            int first = nums[i];
+            int second = i+1, third = nums.Length -1;
+            while(second < third)
+            {
+                if(nums[second] + nums[third] == -first)
+                {
+                    List<int> temp = new();
+                    temp.Add(first);
+                    temp.Add(nums[second]);
+                    temp.Add(nums[third]);
+                    result.Add(temp);
+                    while(second < third && nums[second] == nums[second+1])
+                    second++;
+                    while(second < third && nums[third] == nums[third-1])
+                    third--;
+                    second++;
+                    third--;
+                }
+
+                else if(nums[second] + nums[third] < -first)
+                {
+                    second ++;
+                }
+
+                else
+                {
+                    third --;
+                }
+            }
+        }
+
+        return result;
+    }
+}

Problem3.cs

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+// Time Complexity : O(n) where n is the total length of height array
+// Space Complexity : O(1)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+public class Solution {
+    public int MaxArea(int[] height) {
+        int low = 0, high = height.Length - 1;
+        int maxArea = 0;
+
+        while(low<=high)
+        {
+            int minHeight = Math.Min(height[low], height[high]);
+            maxArea = Math.Max(maxArea, minHeight * (high-low));
+
+            if(height[low] < height[high])
+            {
+                low++;
+            }
+
+            else
+            {
+                high--;
+            }
+        }
+
+        return maxArea;
+    }
+}