The Weekly Challenge

09. TASK #1: Closest Palindrome

HEADLINES

Welcome to the Week #288 of The Weekly Challenge.

Welcome back, Luca Ferrari, and thanks for sharing solutions in Raku, Python, Java and PostgreSQL.

Welcome back, Lubos Kolouch and thanks for sharing solutions in Perl and Python.

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`287`	52	25	28

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`286`	14	50	21
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Blogs with Creative Title

1. Strong and Valid by Arne Sommer.

2. Strength in Numbers by Bob Lied.

3. Common Passwords by Jorg Sommrey.

4. in regexp we trust! by Luca Ferrari.

5. About Passwords, Birds, and Common Regexes by Matthias Muth.

6. Strong but Valid by Packy Anderson.

7. Strong and valid by Peter Campbell Smith.

8. Strong and Valid by Roger Bell_West.

9. Good things by Simon Green.

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RECAP

Quick recap of The Weekly Challenge - 287 by Mohammad Sajid Anwar.

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Task 1: Closest Palindrome

Submitted by: Mohammad Sajid Anwar

You are given a string, $str, which is an integer.

Write a script to find out the closest palindrome, not including itself. If there are more than one then return the smallest.

The closest is defined as the absolute difference minimized between two integers.

Example 1

Input: $str = "123"
Output: "121"

Example 2

Input: $str = "2"
Output: "1"

There are two closest palindrome "1" and "3". Therefore we return the smallest "1".

Example 3

Input: $str = "1400"
Output: "1441"

Example 4

Input: $str = "1001"
Output: "999"

Task 2: Contiguous Block

Submitted by: Peter Campbell Smith

You are given a rectangular matrix where all the cells contain either x or o.

Write a script to determine the size of the largest contiguous block.

A contiguous block consists of elements containing the same symbol which share an edge (not just a corner) with other elements in the block, and where there is a path between any two of these elements that crosses only those shared edges.

Example 1

    Input: $matrix = [
                       ['x', 'x', 'x', 'x', 'o'],
                       ['x', 'o', 'o', 'o', 'o'],
                       ['x', 'o', 'o', 'o', 'o'],
                       ['x', 'x', 'x', 'o', 'o'],
                     ]
    Ouput: 11

        There is a block of 9 contiguous cells containing 'x'.
        There is a block of 11 contiguous cells containing 'o'.

Example 2

    Input: $matrix = [
                       ['x', 'x', 'x', 'x', 'x'],
                       ['x', 'o', 'o', 'o', 'o'],
                       ['x', 'x', 'x', 'x', 'o'],
                       ['x', 'o', 'o', 'o', 'o'],
                     ]
    Ouput: 11

        There is a block of 11 contiguous cells containing 'x'.
        There is a block of 9 contiguous cells containing 'o'.

Example 3

    Input: $matrix = [
                       ['x', 'x', 'x', 'o', 'o'],
                       ['o', 'o', 'o', 'x', 'x'],
                       ['o', 'x', 'x', 'o', 'o'],
                       ['o', 'o', 'o', 'x', 'x'],
                     ]
    Ouput: 7

        There is a block of 7 contiguous cells containing 'o'.
        There are two other 2-cell blocks of 'o'.
        There are three 2-cell blocks of 'x' and one 3-cell.

Last date to submit the solution 23:59 (UK Time) Sunday 29th September 2024.