Update and rename 17 Dice Roll Game.sql to 17 Dice Roll Game Recursion.sql

Author: smpetersgithub

Permutations, Combinations, Sequences and Random Numbers/SQL Scripts/17 Dice Roll Game Recursion.sql

@@ -0,0 +1,170 @@
+DROP TABLE IF EXISTS ##Sales;
+GO
+/*********************************************************************
+Scott Peters
+Dice Roll Game
+https://advancedsqlpuzzles.com
+Last Updated: 07/05/2022
+
+This script is written in SQL Server's T-SQL
+
+
+* Because you cannot go below 0, a WHILE loop is created to account for this scenario
+* You will need to make an assumption how many possible numbers you need in the #Numbers table, as this solution uses windowing
+* This script performs 1 iteration of the Dice Roll Game
+
+**********************************************************************/
+
+-------------------------------
+-------------------------------
+--Tables used
+DROP TABLE IF EXISTS #Numbers;
+DROP TABLE IF EXISTS #DiceRolls;
+DROP TABLE IF EXISTS #DiceRolls_NotSixes;
+DROP TABLE IF EXISTS #DiceRolls_Modified;
+DROP TABLE IF EXISTS #DiceRollsResults;
+GO
+
+-------------------------------
+-------------------------------
+--Declare and set variables
+--Make an assumption on the total number of rolls needed
+DECLARE @vDesiredScore INTEGER = 100;
+DECLARE @vIterations INTEGER = 100;
+
+-------------------------------
+-------------------------------
+--Create and populate a #Numbers table
+WITH cte_Number (Number)
+AS (
+    SELECT 1 AS Number
+    UNION ALL
+    SELECT  Number + 1
+    FROM   cte_Number
+    WHERE  Number < 200 --@vDesiredScore * 2  --Assuming you will not need x times the desired score for the total number of rolls needed to achieve the desired score
+    )
+SELECT Number
+INTO   #Numbers
+FROM   cte_Number
+OPTION (MAXRECURSION 0);--A value of 0 means no limit to the recursion level
+
+-------------------------------
+-------------------------------
+--Create and populate a #DiceRolls table
+WITH cte_Random AS
+(
+SELECT  Number,
+        ABS(CHECKSUM(NEWID()) % 6) + 1 AS DiceRoll,
+        CAST(NULL AS INTEGER) AS DiceResult
+FROM    #Numbers
+)
+SELECT  Number AS StepNumber
+        ,DiceRoll
+INTO    #DiceRolls
+FROM    cte_Random;
+GO
+
+/***************************************
+--If you need to create test data with multiple rolls of 6
+
+UPDATE #DiceRolls
+SET		DiceRoll = 6
+WHERE	StepNumber in (1,3,4,6,7);
+GO
+	
+
+UPDATE #DiceRolls
+SET		DiceRoll = 5
+WHERE	StepNumber in (2,5);
+GO
+***************************************/
+
+-------------------------------
+-------------------------------
+--Create and populate a #DiceRolls_NotSixes table
+SELECT  StepNumber
+        ,LEAD(StepNumber) OVER (ORDER BY StepNumber) - 1 AS Lead_StepNumber
+        ,DiceRoll
+INTO    #DiceRolls_NotSixes
+FROM    #DiceRolls
+WHERE   DiceRoll <> 6;
+GO
+
+-------------------------------
+-------------------------------
+--Create and populate a #DiceRolls_Modified table
+--Determines which StepNumbers need to be subtracted
+WITH cte_DiceRolls AS
+(
+SELECT  a.Number as StepNumber,
+        ISNULL(b.Lead_StepNumber,a.Number) AS Lead_StepNumber,
+        c.DiceRoll AS DiceRoll_Actual,
+        CASE WHEN a.Number = b.StepNumber THEN b.DiceRoll ELSE ISNULL(b.DiceRoll,0) * - 1 END AS DiceRoll_Modified
+FROM    #Numbers a LEFT OUTER JOIN
+        #DiceRolls_NotSixes b ON a.Number BETWEEN b.StepNumber AND b.Lead_StepNumber
+        LEFT OUTER JOIN
+        #DiceRolls c ON a.Number = c.StepNumber
+)
+SELECT  1 AS ID,
+        StepNumber,
+        Lead_StepNumber,
+        DiceRoll_Actual,
+        DiceRoll_Modified,
+        SUM(DiceRoll_Modified) OVER (ORDER BY StepNumber) AS DiceRoll_Sum
+INTO    #DiceRolls_Modified
+FROM    cte_DiceRolls;
+GO
+
+-------------------------------
+-------------------------------
+--Create and populate a #DiceRollsResults table
+--Uses recursion to account for the sum not allowed to go below 0
+;WITH cte_DiceRolls_Modified AS
+(
+--Add a ranking function here if needed
+--Test data has StepNumber to rank/sort the records.
+SELECT  *
+FROM    #DiceRolls_Modified
+),
+cte_Recursion AS
+(
+SELECT  ID,
+        StepNumber,
+        DiceRoll_Actual,
+        DiceRoll_Modified,
+        DiceRoll_Sum,
+        CASE WHEN DiceRoll_Modified < 0 THEN 0
+             WHEN DiceRoll_Modified > 1000 THEN 1000
+             ELSE DiceRoll_Modified
+        END AS DiceRoll_Sum_Modified 
+FROM    #DiceRolls_Modified
+WHERE StepNumber = 1
+UNION ALL
+SELECT  cte.ID,
+        t.StepNumber,
+        t.DiceRoll_Actual,
+        t.DiceRoll_Modified,
+        t.DiceRoll_Sum,
+        (CASE WHEN t.DiceRoll_Modified + cte.DiceRoll_Sum_Modified < 0 THEN 0
+              WHEN t.DiceRoll_Modified + cte.DiceRoll_Sum_Modified > 1000 THEN 1000
+              ELSE t.DiceRoll_Modified + cte.DiceRoll_Sum_Modified
+        END) AS RunningSum
+FROM    cte_Recursion cte
+        INNER JOIN
+        cte_DiceRolls_Modified t ON t.StepNumber = (cte.StepNumber + 1) AND t.ID = cte.ID
+)
+SELECT   *
+INTO     #DiceRollsResults
+FROM     cte_Recursion
+ORDER BY ID,
+         StepNumber
+OPTION (MAXRECURSION 0);--A value of 0 means no limit to the recursion level;
+GO
+
+-------------------------------
+-------------------------------
+--Display the results
+SELECT  * 
+FROM    #DiceRollsResults
+WHERE   StepNumber <= (SELECT MIN(StepNumber) FROM #DiceRollsResults WHERE DiceRoll_Sum_Modified >= 100)
+ORDER BY StepNumber DESC;