Equilibrium index: Difference between revisions

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=={{header|RPL}}==

{| class="wikitable"

! RPL code

! Comment

|-

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≪

0 SWAP + → seq

≪ { } 0 seq ∑LIST

2 seq SIZE '''FOR''' j

seq j GET - SWAP seq j 1 - GET + SWAP

'''IF''' DUP2 == '''THEN''' ROT j 2 - + ROT ROT '''END'''

'''NEXT''' DROP2

≫ ≫ ‘'''EQIDX'''’ STO

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'''EQIDX''' ''( { A0..An } -- { equilibrium index } ) ''

add zero at list head to avoid GET error at first loop

left = 0 ; right = A0+A1+...An

loop from j=2 to length(seq) e.g. A0 to An

right -= seq[j] ; left += A[j-1]

if left = right then append j-2 to index list

drop left and right

return list

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{ -7 1 5 2 -4 3 0 } EQIDX

{{out}}

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1: { 3 6 }