Balanced brackets: Difference between revisions
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(→{{header|Perl}}: fixed brain damage) |
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Straightforward depth counting: |
Straightforward depth counting: |
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<lang Perl>use 5.10.0; # for given ... when construct |
<lang Perl>use 5.10.0; # for given ... when construct |
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sub balanced2 { |
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sub balanced { |
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my $depth = 0; |
my $depth = 0; |
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my @a = split('', shift); |
my @a = split('', shift); |
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for (0 .. $#a) { |
for my $i (0 .. $#a) { |
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given($a[$ |
given($a[$i]) { |
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when('[') { ++$depth } |
when('[') { ++$depth } |
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when(']') { return if --$depth < 0 } |
when(']') { return if --$depth < 0 } |
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} |
} |
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} |
} |
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for (']', '[', '[[]', ' |
for (']', '[', '[[]', '][]', '[[]]', '[[]]]][][]]', 'x[ y [ [] z ]][ 1 ][]abcd') { |
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print balanced($_) ? " |
print balanced($_) ? "" : "not ", "balanced:\t'$_'\n"; |
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}</lang> |
}</lang> |
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sub balanced { |
sub balanced { |
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my $_ = shift; |
my $_ = shift; |
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s/(\[(?:[^\[\]]++|(?1))*\])//g; |
s/(\[(?:[^\[\]]++|(?1))*\])//g; |
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/[\[\]]/; |
! /[\[\]]/; |
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} |
} |
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for (']', '[', '[[]', ' |
for (']', '[', '[[]', '][]', '[[]]', '[[]]]][][]]', 'x[ y [ [] z ]][ 1 ][]abcd') a{ |
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print balanced($_) ? " |
print balanced($_) ? "" : "not ", "balanced:\t'$_'\n"; |
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}</lang> |
}</lang> |
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Both methods |
Both methods print |
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<pre>balanced: |
<pre>not balanced: ']' |
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balanced: |
not balanced: '[' |
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balanced: |
not balanced: '[[]' |
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balanced: |
not balanced: '][]' |
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balanced: '[[]]' |
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balanced: |
not balanced: '[[]]]][][]]' |
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balanced: 'x[ y [ [] z ]][ 1 ][]abcd' |
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</pre> |
</pre> |
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The counting method could easily give where the first unbalanced bracket occured, though. |
The counting method could easily give where the first unbalanced bracket occured, though. |
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