Re: About Div

From: Otniel Michael <otmic_ie(at)yahoo(dot)com>
To: Aaron Bono <postgresql(at)aranya(dot)com>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: About Div
Date: 2006-07-26 01:43:28
Message-ID: 20060726014328.38920.qmail@web53202.mail.yahoo.com
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Mr. Aaron. I am sorry, your solution didn't match in my case.
Example for your solution :
A = 1
B = 1
C = 1
D = 1
E = 1
F = 1
G = 4

G have 4 candy. Its too much for G.

In my case, the solution is :
A = 1
B = 1
C = 1
D = 1
E = 2
F = 2
G = 2

The extra candy is given to three child.

Do you have the other solution? I need function in postgresql for my case.
Because my loop is too slow.

Btw thanks for your solution.

Aaron Bono <postgresql(at)aranya(dot)com> wrote: On 7/25/06, Otniel Michael <otmic_ie(at)yahoo(dot)com> wrote: Dear All,

I have a problem with this case :

I have 10 candy for 7 child (A, B, C, D, E, F, G).

Table X :
code value
------- --------
A 0
B 0
C 0
D 0
E 0
F 0
G 0

And I want divide it with this algorithm :
A = 10 / 7 = 1
B = (10-1) / (7-1) = 9 / 6 = 1
C = (10-2) / (7-2) = 8 / 5 = 1
D = (10-3) / (7-3) = 7 / 4 = 1
E = (10-4) / (7-4) = 6 / 3 = 2
F = (10-6) / (7-5) = 4 / 2 = 2
G = (10-8) / (7-6) = 2 / 1 = 2

In my first solution i use loop - for each record in my function.
But it is too slow in a lot of data.
Did postgresql have a function for my case?


No loop necessary. This is a simple math problem:

dividedamount := candy / childcount;
extra = candy % childcount;

So the first (childcount - extra) get (dividedamount) pieces of candy and the last (extra) get (dividedamount + 1) pieces of candy.

==================================================================
Aaron Bono
Aranya Software Technologies, Inc.
http://www.aranya.com
==================================================================

--
"He who is quick to become angry will commit folly, and a crafty man is hated"

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