如何反转这个散列函数? [英] How do I reverse this hashing function?

问题描述

我们的想法是使用此脚本获取产生此数字的 7 个字符长字符串:3552907293224:

The idea is to get what is the 7 characters long string that produces this number: 3552907293224 with this script:

sub hash {
     my $nr = 13;
     for (split //, shift) {
          $nr = $nr * 43 + index("acdegijmnoprstuw", $_);
     }
     return $nr;
}

我设法找出了它是eddigjo"的字符串(通过手动尝试)，但我需要一个函数来反向跟踪可能生成上述数字的内容.

I managed to figure out the string it's "eddigjo" (with manual trying), but I need a function that reverse traces what could possibly genereate the number mentioned above.

推荐答案

即使你不努力解决问题，我也会咬牙切齿:

I'll bite, even though you put no effort into solving the problem:

use strict;
use warnings;

use feature qw(say);

my @alphabet = split //, "acdegijmnoprstuw";   #/
sub reverse_hash {
    my ($n) = @_;

    my @letters;
    while ( $n > 43 ) {
        unshift @letters, $alphabet[$n % 43];
        $n /= 43;
    }

    return join '', @letters;
}

say reverse_hash(3552907293224);
# eddigjo

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