New tasks

6. Zigzag Conversion/Solution.cs

@@ -0,0 +1,41 @@
+using System.Text;
+
+namespace _6._Zigzag_Conversion;
+
+public class Solution {
+    public string Convert(string s, int numRows)
+    {
+        if (numRows == 1)
+            return s;
+        int stepDown = (numRows-2) * 2 + (numRows>0 ? 1 : 0);
+        int stepTop = 0;
+        StringBuilder sb = new StringBuilder();
+        for (int start = 0; start < numRows; start++)
+        {
+            int j = start;
+            bool toDown = true;
+            while (j<s.Length)
+            {
+                sb.Append(s[j]);
+                if (stepDown == 0)
+                    j += stepTop;
+                else if (stepTop == 0)
+                    j += stepDown;
+                else if (toDown)
+                    j += stepDown;
+                else
+                    j += stepTop;
+                j++;
+                toDown = !toDown;
+            }
+            stepDown -= 2;
+            if (stepDown < 0)
+                stepDown = 0;
+            if (stepTop == 0)
+                stepTop = 1;
+            else
+                stepTop += 2;
+        }
+        return sb.ToString();
+    }
+}