PHP Exercises: Check a given array of integers and return true if there is a 3 with a 5 somewhere later in the given array

Last update on May 30 2022 11:41:39 (UTC/GMT +8 hours)

PHP Basic Algorithm: Exercise-118 with Solution

Write a PHP program to check a given array of integers and return true if there is a 3 with a 5 somewhere later in the given array.

Sample Solution:

PHP Code :

<?php
function test($numbers)
 { 
    $three = false;

    for ($i = 0; $i < sizeof($numbers); $i++)
            {
               if ($three && $numbers[$i] == 5) return true;
               if ($numbers[$i] == 3) $three = true;
            }
        return false;
 }   

var_dump(test([3, 5, 1, 3, 7]));
var_dump(test([1, 2, 3, 4]));
var_dump(test([3, 3, 5, 5, 5, 5]));
var_dump(test([2, 5, 5, 7, 8, 10]));

Sample Output:

bool(true)
bool(false)
bool(true)
bool(false)

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to check a given array of integers and return true if the given array contains two 5's next to each other, or two 5 separated by one element.
Next: Write a PHP program to check a given array of integers and return true if the given array contains either 2 even or 2 odd values all next to each other.

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