PHP Exercises: Compare two given strings and return the number of the positions where they contain the same length 2 substring

Last update on May 30 2022 11:41:18 (UTC/GMT +8 hours)

PHP Basic Algorithm: Exercise-35 with Solution

Write a PHP program to compare two given strings and return the number of the positions where they contain the same length 2 substring.

Sample Solution:

PHP Code :

<?php
function test($s1, $s2)
{
    $ctr = 0;
            for ($i = 0; $i < strlen($s1)-1; $i++)
            {
                $firstString = substr($s1, $i, 2);
                for ($j = 0; $j < strlen($s2)-1; $j++)
                {
                    $secondString = substr($s2, $j, 2);
                    if ($firstString == $secondString) 
                    $ctr++;
                }
            }
            return $ctr;
 }

echo (test("abcdefgh", "abijsklm"))."\n";
echo (test("abcde", "osuefrcd"))."\n";
echo (test("pqrstuvwx", "pqkdiewx"))."\n";

Sample Output:

1
1
2

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to check whether the sequence of numbers 1, 2, 3 appears in a given array of integers somewhere.
Next: Write a PHP program to create a new string of the characters at indexes 0,1,4,5,8,9 ... from a given string.

What is the difficulty level of this exercise?

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC