71 lines
1.7 KiB
Fortran
71 lines
1.7 KiB
Fortran
recursive subroutine fpfrno(maxtr,up,left,right,info,point,
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* merk,n1,count,ier)
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implicit none
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c subroutine fpfrno collects the free nodes (up field zero) of the
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c triply linked tree the information of which is kept in the arrays
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c up,left,right and info. the maximal length of the branches of the
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c tree is given by n1. if no free nodes are found, the error flag
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c ier is set to 1.
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c ..
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c ..scalar arguments..
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integer maxtr,point,merk,n1,count,ier
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c ..array arguments..
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integer up(maxtr),left(maxtr),right(maxtr),info(maxtr)
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c ..local scalars
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integer i,j,k,l,n,niveau
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c ..
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ier = 1
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if(n1.eq.2) go to 140
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niveau = 1
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count = 2
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10 j = 0
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i = 1
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20 if(j.eq.niveau) go to 30
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k = 0
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l = left(i)
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if(l.eq.0) go to 110
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i = l
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j = j+1
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go to 20
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30 if (i.lt.count) go to 110
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if (i.eq.count) go to 100
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go to 40
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40 if(up(count).eq.0) go to 50
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count = count+1
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go to 30
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50 up(count) = up(i)
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left(count) = left(i)
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right(count) = right(i)
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info(count) = info(i)
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if(merk.eq.i) merk = count
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if(point.eq.i) point = count
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if(k.eq.0) go to 60
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right(k) = count
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go to 70
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60 n = up(i)
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left(n) = count
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70 l = left(i)
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80 if(l.eq.0) go to 90
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up(l) = count
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l = right(l)
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go to 80
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90 up(i) = 0
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i = count
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100 count = count+1
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110 l = right(i)
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k = i
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if(l.eq.0) go to 120
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i = l
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go to 20
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120 l = up(i)
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j = j-1
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if(j.eq.0) go to 130
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i = l
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go to 110
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130 niveau = niveau+1
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if(niveau.le.n1) go to 10
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if(count.gt.maxtr) go to 140
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ier = 0
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140 return
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end
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