Php Program for Minimum rotations required to get the same string

Given a string, we need to find the minimum number of rotations required to get the same string. Examples:

Input : s = "geeks"
Output : 5

Input : s = "aaaa"
Output : 1

The idea is based on below post. A Program to check if strings are rotations of each other or not Step 1 : Initialize result = 0 (Here result is count of rotations) Step 2 : Take a temporary string equals to original string concatenated with itself. Step 3 : Now take the substring of temporary string of size same as original string starting from second character (or index 1). Step 4 : Increase the count. Step 5 : Check whether the substring becomes equal to original string. If yes, then break the loop. Else go to step 2 and repeat it from the next index. 

PHP

<?php
// PHP program to determine minimum
// number of rotations required to
// yield same string.

// Returns count of rotations
// to get the same string back.
function findRotations($str)
{
    // tmp is the concatenated string.
    $tmp = ($str + $str);
    $n = strlen($str);

    for ( $i = 1; $i <= $n; $i++)
    {

        // substring from i index
        // of original string size.
        $substring = $tmp.substr($i,
                          strlen($str));

        // if substring matches with
        // original string then we will
        // come out of the loop.
        if ($str == $substring)
            return $i;
    }
    return $n;
}

// Driver code
$str = "abc";
echo findRotations($str), "
";

// This code is contributed
// by Sachin
?>

Output: 

3

Time Complexity: O(n²) Please refer complete article on Minimum rotations required to get the same string for more details!
Auxiliary Space: O(n), The extra space is used to store the copied string in tmp variable.