PHP Exercises: Check a given array of integers and return true if every 5 that appears in the given array is next to another 5

Last update on May 28 2025 13:07:10 (UTC/GMT +8 hours)

121. Check Every 5 is Paired with Another

Write a PHP program to check a given array of integers and return true if every 5 that appears in the given array is next to another 5.

Sample Solution:

PHP Code :

<?php
// Define a function named 'test' that takes an array of numbers as a parameter
function test($numbers)
 { 
    // Calculate the length of the array
    $arr_len = sizeof($numbers);

    // Initialize a variable $flag with a value of true
    $flag = true;

    // Iterate through the elements of the array using a for loop
    for ($i = 0; $i < $arr_len; $i++)
    {
        // Check if the current element is 5
        if ($numbers[$i] == 5)
        {
            // Check if there is a consecutive 5 before or after the current element
            if (($i > 0 && $numbers[$i - 1] == 5) || ($i < $arr_len - 1 && $numbers[$i + 1] == 5))
                $flag = true;
            // Check if the current element is the last element in the array
            else if ($i == $arr_len - 1)
                $flag = false;
            else
                return false;
        }
    }

    // Return the value of $flag after iterating through the array
    return $flag;
 }   

// Use 'var_dump' to print the result of calling 'test' with different arrays
var_dump(test([3, 5, 5, 3, 7]));
var_dump(test([3, 5, 5, 4, 1, 5, 7]));
var_dump(test([3, 5, 5, 5, 5, 5]));
var_dump(test([2, 4, 5, 5, 6, 7, 5]));
?>

Sample Output:

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

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to verify that in a given array every occurrence of 5 has at least one adjacent 5.
Write a PHP function to iterate through an array and return true if each 5 is immediately next to another 5.
Write a PHP program to check pairs of elements in an array such that if an element equals 5 it is adjacent to another 5.
Write a PHP script to use flag variables to validate that every 5 in the array is coupled with at least one neighboring 5.

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