Create 0171-excel-sheet-column-number.cs

Author: dmitry-ivashenko

csharp/0171-excel-sheet-column-number.cs

@@ -0,0 +1,16 @@
+public class Solution {
+    public int TitleToNumber(string columnTitle) {
+        int result = 0;
+        char[] chars = columnTitle.ToCharArray().Reverse().ToArray();
+
+        for (int index = 0; index < chars.Length; index++) {
+            char currentChar = chars[index];
+            int delta = currentChar - 'A' + 1;
+            int sum = delta * (int)Math.Pow(26, index);
+
+            result += sum;
+        }
+
+        return result;
+    }
+}