//Your color codes
        $str1 = "000000 f0f0f0 c0c0c0 202020 404040 ";
        $str2 = "0000ee 555333 cc0000 602040 003399 ";
        $str3 = "9999cc 0000cc 0099ff 204010 552299 ";
        $str4 = "406040 ffffff ffcccc 000000 202020 ";
        $str5 = "cc0000 99ffcc cc9900 ff9999 000000 ";

    //creating an array and merging all codes
        $final_arr = array_merge( explode(" ",$str1),explode(" ",$str2),explode(" ",$str3),explode(" ",$str4),explode(" ",$str5) );

    //removing all empty elements
        $final_arr = array_filter($final_arr);

        //echo \'<pre>\'; print_r($final_arr); echo \'</pre>\';

    //Getting count of each element
        $vals = array_count_values($final_arr);

        //echo \'<pre>\'; print_r($vals); echo \'</pre>\';

    //Sorting array in high to low order
        arsort($vals);

//Getting first 3 elements with highest count
        $first_n = array_slice($vals, 0, 3,true);

        echo \'<pre>\'; print_r($first_n); echo \'</pre>\';

    //Output
    Array
    (
        [000000] => 3
        [cc0000] => 2
        [202020] => 2
    )