Evil Science A whole load of stuff


Project Euler Problem 61 Solution in TSQL

	generate the number range
create table #polygonalnumbers 
	ctr int
	, val bigint
	, poltype varchar(3)

declare @ctr as integer 
set @ctr = 1

while (@ctr < 1000)

		insert into #polygonalnumbers
		select	@ctr,(@ctr*(@ctr+1))/2,'tri'

		insert into #polygonalnumbers
		select	@ctr,@ctr * @ctr *@ctr,'sqr'
		insert into #polygonalnumbers
		select	@ctr,(@ctr*((3*@ctr)-1))/2	,'pnt'	
		insert into #polygonalnumbers
		select	@ctr,(@ctr*((2*@ctr)-1))	,'hex'		
		insert into #polygonalnumbers
		select	@ctr,(@ctr*((5*@ctr)-3))/2	,'hep'		
		insert into #polygonalnumbers
		select	@ctr,(@ctr*((3*@ctr)-2))	,'oct'		
		set @ctr = @ctr + 1
	delete from	#polygonalnumbers
	where   LEN(val) <> 4
	output the answer
select	distinct  num1.val + num2.val + num3.val + num4.val + num5.val + num6.val

from	#polygonalnumbers num1
		inner join #polygonalnumbers num2
			on RIGHT (num1.val,2) = LEFT(num2.val,1)
			and num2.poltype <> num1.poltype
		inner join #polygonalnumbers num3
			on RIGHT (num2.val,2) = LEFT(num3.val,2)
			and num3.poltype <> num2.poltype
			and num3.poltype <> num1.poltype
		inner join #polygonalnumbers num4
			on RIGHT (num3.val,2) = LEFT(num4.val,2)
			and num4.poltype <> num3.poltype
			and num4.poltype <> num2.poltype
			and num4.poltype <> num1.poltype
		inner join #polygonalnumbers num5
			on RIGHT (num4.val,2) = LEFT(num5.val,2)
			and num5.poltype <> num4.poltype
			and num5.poltype <> num3.poltype
			and num5.poltype <> num2.poltype
			and num5.poltype <> num1.poltype
		inner join #polygonalnumbers num6
			on RIGHT (num5.val,2) = LEFT(num6.val,2)
			and num6.poltype <> num5.poltype
			and num6.poltype <> num4.poltype
			and num6.poltype <> num3.poltype
			and num6.poltype <> num2.poltype
			and num6.poltype <> num1.poltype
			and RIGHT (num6.val,2) = LEFT(num1.val,2)

Easy! There are, however, a couple of deliberate errors, that can be easily located with some patience. I don't want to make things to easy for you little scamps, do I?

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