Task: Your function should return a valid regular expression. This is a pattern which is normally used to match parts of a string. In this case will be used to check if all the characters given in the input appear in a string.

Input Non empty string of unique alphabet characters upper and lower case.

Output Regular expression pattern string.

Examples Your function should return a string.

public static String regexContainsAll(str) { return "abc"; } That regex pattern will be tested like this.

String abc = "abc"; String pattern = regexContainsAll(abc); String str = "zzzaaacccbbbzzz"; Pattern.compile(pattern).matcher(str).find(); // -> true