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Solutions to weekly challenge 74 by Bob Lied.
https://perlweeklychallenge.org/blog/perl-weekly-challenge-074/
* TASK #1 > Majority Element
** Initial thoughts
This is going to be an exercise in hashes and grep.
** Post Solution Thoughts
Use a hash to count to count elements, then use grep with a code block to select the match.
** Problem Statement
You are given an array of integers of size $N.
Write a script to find the majority element. If none found then print -1.
Majority element in the list is the one that appears more than floor(size_of_list/2).
* TASK #2 > FNR Character
** Initial Thoughts
The specification is a little odd and doesn't match the example. But, OK, whatever.
Similar to the first task, another hash to count occurrences and grep to find the answers.
** Post Solution Thoughts
Going through the string could be either done with substr one character at a time,
or splitting the string into an array of characters. Finding the first char could be
a search through the character positions, or a sort and picking off the first element.
Sort is the easy answer, but I'm always wary of scaling. Like in many of these
problems, it's not an issue for "reasonable" strings, but could become a performance
question if the strings were a thousand or a million times bigger.
** Problem Statement
You are given a string $S.
Write a script to print the series of first non-repeating character
(left -> right) for the given string. Print # if none found.
Example 1
Input: $S = ‘ababc’
Output: ‘abb#c’
Pass 1: “a”, the FNR character is ‘a’
Pass 2: “ab”, the FNR character is ‘b’
Pass 3: “aba”, the FNR character is ‘b’
Pass 4: “abab”, no FNR found, hence ‘#’
Pass 5: “ababc” the FNR character is ‘c’
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