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| -rw-r--r-- | challenge-050/cheok-yin-fung/perl/ch-1.pl | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/challenge-050/cheok-yin-fung/perl/ch-1.pl b/challenge-050/cheok-yin-fung/perl/ch-1.pl new file mode 100644 index 0000000000..e7c3294ba5 --- /dev/null +++ b/challenge-050/cheok-yin-fung/perl/ch-1.pl @@ -0,0 +1,71 @@ +#!/usr/bin/perl +use strict; +use warnings; + +# Caution: The following codes work for distinct interval heads only. + +my @L = (0) x 100; +$L[100] = 1; +$L[101] = -1; +my %interval; # key: the head of the interval; value: the tail of the interval + +sub newroute { + for my $i ($_[0]..$_[1]) {$L[$i]++;} + $interval{$_[0]}=$_[1]; +} + + + +newroute(2,7); +newroute(3,9); +newroute(10,12); +newroute(15,19); +newroute(18,22); + +newroute(100,100); # a temporary arrangement +my @trainstation = sort {$a <=> $b} keys %interval; + +my %finterval; # key: the head of the interval; value: the tail of the interval + + +my $stationnum = 0; + + + +sub seektermination { + my $i = $_[0]; + my $nextstop = $_[1]; + while ($L[$i] > 0 and $i < $nextstop) { + $i++; + } + + if ($L[$i] == 0 and $i<$nextstop) { + return $i-1; + } + if ($L[$i]>1) { + $stationnum++; + return seektermination($_[0], $trainstation[$stationnum+1]); + } + if ($i==$nextstop and $L[$i-1] == 1 and $L[$i]==1) { + return $i-1; + } +} + + + + + + +while ($stationnum<=$#trainstation-1) { + my $start = $trainstation[$stationnum]; + $finterval{$start} = seektermination($start, $trainstation[$stationnum+1]); + $stationnum++; +} + + +delete $finterval{100}; #goodbye to the temporary arrangement +foreach my $s (sort {$a <=> $b} keys %finterval) { + print "[", $s, ", ", $finterval{$s}, "]", "\n"; +} + + |