PHP Exercises: Check if a triple is presents in an array of integers or not

Last update on May 28 2025 13:07:48 (UTC/GMT +8 hours)

38. Detect Triple Consecutive Occurrence

Write a PHP program to check if a triple is presents in an array of integers or not. If a value appears three times in a row in an array it is called a triple.

Sample Solution:

PHP Code :

<?php
// Define a function that checks for consecutive identical elements in an array
function test($nums)
{
    // Calculate the length of the array
    $arra_len = sizeof($nums) - 1;

    // Initialize a variable to store the current element
    $n = 0;

    // Iterate through the array up to the second-to-last element
    for ($i = 0; $i < $arra_len; $i++)
    {
        // Retrieve the current element
        $n = $nums[$i];

        // Check if the current, next, and next-next elements are identical
        if ($n == $nums[$i + 1] && $n == $nums[$i + 2])
        {
            // Return true if the condition is met
            return true;
        }
    }

    // Return false if the condition is not met
    return false;
}

// Test the function with different arrays
var_dump(test(array(1, 1, 2, 2, 1)));
var_dump(test(array(1, 1, 2, 1, 2, 3)));
var_dump(test(array(1, 1, 1, 2, 2, 2, 1)));
?>

Explanation:

Function Definition:

The test function accepts an array of numbers, $nums, and checks if it contains three consecutive identical elements.

Array Length Calculation:

$arra_len is set to the length of $nums minus 1, allowing the loop to safely access the last set of three consecutive elements.

Loop through the Array:

A for loop iterates through $nums up to the second-to-last element, ensuring that $nums[$i + 2] is a valid index.

Retrieve Current Element:

The current element $n is set to $nums[$i].

Check for Three Consecutive Identical Elements:

The if statement checks if the current element $n is equal to the next two elements ($nums[$i + 1] and $nums[$i + 2]).
If this condition is met, the function immediately returns true, indicating three consecutive identical elements were found.

Return false if No Consecutive Identicals Found:

If the loop completes without finding three consecutive identical elements, the function returns false.

Output:

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

Visual Presentation:

PHP Basic Algorithm Exercises: Check if a triple is presents in an array of integers or not.

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to check if any value appears three times in a row within an array.
Write a PHP function to iterate over an array and return true if it finds any triple consecutive occurrence of the same number.
Write a PHP program to evaluate an array for sequences of three identical integers in immediate succession.
Write a PHP script to use loop-based logic to detect triplets in a numerical array and return a boolean flag.

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