diff --git a/Ch 01. Arrays and Strings/Q1_03_URLify.cs b/Ch 01. Arrays and Strings/Q1_03_URLify.cs
index 4f5ea09..16b3eb3 100644
--- a/Ch 01. Arrays and Strings/Q1_03_URLify.cs	
+++ b/Ch 01. Arrays and Strings/Q1_03_URLify.cs	
@@ -21,7 +21,7 @@ private void ReplaceSpaces(char[] input, int length)
             var space = new[] { '0', '2', '%' };
             var spaceCount = Count_the_number_of_spaces(input);
             // calculate new string size
-            var index = length + spaceCount * 2;
+            var index = length + spaceCount * 2 -1;
             void SetCharsAndMoveIndex(params char[] chars)
             {
                 foreach (var c in chars)
@@ -37,7 +37,7 @@ void SetCharsAndMoveIndex(params char[] chars)
         public override void Run()
         {
             const string input = "abc d e f";
-            var characterArray = new char[input.Length + 3 * 2 + 1];
+            var characterArray = new char[input.Length + 3 * 2];
 
             for (var i = 0; i < input.Length; i++)
             {
@@ -48,4 +48,4 @@ public override void Run()
             Console.WriteLine("{0} -> {1}", input, new string(characterArray));
         }
     }
-}
\ No newline at end of file
+}