1) as you go through the data looking for numbers put the found numbers in a hash a remeber the largest one found. then at the end:

my @array = map { $hash{$_} ? "$_.found" : "$_.lost" } 1 .. $max_found
+;
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2) generate @array with:

$array[$number] = "$number.found";
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when you're done:

@array = map { $array[$_] ? $array[$_] : "$_.lost" } 1 .. $#array;
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