A cute little problem

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Article #65

#65

From: Greg Johnson
Date: Wed, 17 Aug 1983 04:37

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Here's a cute problem I just saw in a magazine called APL Market News.
For any positive integer N, compute the sum of 1 through N-1.  The
problem is to find a short APL expression to do this.  Believe it or not,
this can be done using three characters, one of which is 'N'!
(That was a hint.)
The solution follows (after some space to give you time to stop this so
you can think about it.)
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The solution:  2!N
The problem and solution were submitted to the magazine by Kevin
Farrell of Long Beach, Ca.

						Greg Johnson
						U. of Wisconsin - Madison
						...seismo!uwvax!greg
						greg@uwisc

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Path: arc1-ca.pugleaf.net!utzoo!linus!decvax!harpo!seismo!uwvax!greg
From: greg@uwvax.ARPA (Greg Johnson)
Newsgroups: net.lang.apl
Subject: A cute little problem
Message-ID: <1026@uwvax.ARPA>
Date: Wed, 17-Aug-83 00:37:53 EDT
Article-I.D.: uwvax.1026
Posted: Wed Aug 17 00:37:53 1983
Date-Received: Thu, 11-Aug-83 17:01:26 EDT
Organization: U of Wisconsin CS Dept
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