How can the functions in the PHP code be redesigned to reduce code duplication and improve maintainability?

The functions in the PHP code can be redesigned by creating a common function that encapsulates the shared functionality and can be reused by other functions. This will reduce code duplication and improve maintainability by centralizing the logic in one place.

<?php

function commonFunction($input) {
    // Shared functionality here
}

function function1($input1) {
    // Function 1 specific code
    commonFunction($input1);
}

function function2($input2) {
    // Function 2 specific code
    commonFunction($input2);
}

// Example usage
function1($input1);
function2($input2);

?>