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#!/usr/bin/env perl
# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu:
#=============================================================================
# Copyright (c) 2025, Bob Lied
#=============================================================================
# ch-1.pl Perl Weekly Challenge 328 Task 1 Replace all ?
#=============================================================================
# You are given a string containing only lower case English letters and ?.
# Write a script to replace all ? in the given string so that the string
# doesn’t contain consecutive repeating characters.
# Example 1 Input: $str = "a?z"
# Output: "abz"
# There can be many strings, one of them is "abz". The choices are 'a'
# to 'z' but we can't use either 'a' or 'z' to replace the '?'.
# Example 2 Input: $str = "pe?k"
# Output: "peak"
# Example 3 Input: $str = "gra?te"
# Output: "grabte"
#=============================================================================
use v5.40;
use Getopt::Long;
my $Verbose = false;
my $DoTest = false;
my $Benchmark = 0;
GetOptions("test" => \$DoTest, "verbose" => \$Verbose, "benchmark:i" => \$Benchmark);
my $logger;
{
use Log::Log4perl qw(:easy);
Log::Log4perl->easy_init({ level => ($Verbose ? $DEBUG : $INFO ),
layout => "%d{HH:mm:ss.SSS} %p{1} %m%n" });
$logger = Log::Log4perl->get_logger();
}
#=============================================================================
my %replace = ( "a?a" => "b", "a?b" => "c",
"b?b" => "a", "b?a" => "c", );
exit(!runTest()) if $DoTest;
exit( runBenchmark($Benchmark) ) if $Benchmark;
say replaceQ($_) for @ARGV;
#=============================================================================
sub replaceQ($str)
{
my $pos = 0;
while ( ($pos = index($str, "?", $pos)) != -1 )
{
my $before = substr($str, $pos-1, 1);
my $after = substr($str, $pos+1, 1);
my $instead = ( $before eq 'a' || $after eq 'a' ) ? 'b' : 'a';
$instead = 'c' if ( $before eq $instead || $after eq $instead );
substr($str, $pos, 1, $instead);
}
return $str;
}
sub runTest
{
use Test2::V0;
is( replaceQ("a?z" ), "abz" , "Example 1");
is( replaceQ("pe?k" ), "peak" , "Example 2");
is( replaceQ("gra?te"), "grabte", "Example 3");
is( replaceQ("abcde" ), "abcde" , "No question marks");
is( replaceQ("?abcd" ), "babcd" , "Leading");
is( replaceQ("abcd?" ), "abcda" , "Trailing");
is( replaceQ("a?b" ), "acb" , "Can't be a or b");
is( replaceQ("x???z" ), "xabaz" , "Multiple question marks");
done_testing;
}
sub runBenchmark($repeat)
{
use Benchmark qw/cmpthese/;
cmpthese($repeat, {
label => sub { },
});
}
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