From: Daniel Martin <martin@...>
Date: 2006-06-26T11:29:20+09:00
Subject: Re: [QUIZ] pp Pascal (#84) [SOLUTION]

Erik Veenstra <erikveen@dds.nl> writes:

>  row    = [1, 4, 6, 4, 1]
>  p ([0]+row).zip(row<<0).map{|a,b|a+b}  ===> [1, 5, 10, 10, 5, 1]
>  p row.zip([0]+row).map{|a,b|a+b}+[1]   ===> [1, 5, 10, 10, 5, 1, 1]
>
> Different results...

  row    = [1, 4, 6, 4, 1]
  p ([0]+row).zip(row<<0).map{|a,b|a+b}  ===> [1, 5, 10, 10, 5, 1]
  row    = [1, 4, 6, 4, 1]
  p row.zip([0]+row).map{|a,b|a+b}+[1]   ===> [1, 5, 10, 10, 5, 1]

Running your code first mangles the value of "row".  It's not fair if
you don't give the same value for "row" to my code :)

Incidentally:

  row    = [1, 4, 6, 4, 1]
  p ([0]+row).zip(row<<0).map{|a,b|a+b}  ===> [1, 5, 10, 10, 5, 1]
  p ([0]+row).zip(row<<0).map{|a,b|a+b}  ===> [1, 5, 10, 10, 5, 1, 0]

>>    t=(0..n).map{|i|r=1;[1]+(1..i).map{|a|r=r*(i+1-a)/a}}
>
> Add one extra dot (0...n instead of 0..n) and you win!

Yeah; I'm not surprised I had an off-by-one error - what the quiz
calls the first row I'd call the "zeroth" row.