Chainlink CODE100 challlenge

Star challenge.md

Chainlink challenge

Given a string s, where * represents a star…

Remove the star along with its closest non-star character to its left in a single operation.

The task is to perform this operation until all stars have been removed and to return the string that remains.

Assumptions

• Input s is always a string and the characters are lowercase only
• There will be no consecutive stars (eg “ab***f”) - every star will be followed by a character or be the end of the string.
• Assume s has a length larger than 0 and smaller than 1000

Examples (test cases!)

chainlink → chainlink
chaa*inlinn*k → chainlink
abc*de*f  → abdf
a*b*c*d →  d
abcd → abcd
abc*de*  → abd

You can use this JSON object to test your function.

Submit your solutions at this gist - we'll pick the one we like the best and get you something nice.

I've got 2 answers, one with regex, the other one without. You can choose the one you prefer!

private static String cleanStringRegex(String input) {
        return input.replaceAll(".\\*", "").replace("*", "");
    }

private static String cleanString(String input) {
        if (!input.contains("*")) {
            return input;
        }

        int index = input.indexOf("*");
        int pos = 0;

        StringBuilder result = new StringBuilder();

        //We don't want to change the input
        String tmpInput = input;

        //Clean up the * at the beginning of the string
        while (index == 0) {
            tmpInput = tmpInput.substring(1);
            index = tmpInput.indexOf("*");
        }

        while (index > 0) {
            result.append(tmpInput, pos, index-1);
            pos = index + 1;
            index = tmpInput.indexOf("*", pos);
        }
        //Don't forget the last part!
        result.append(tmpInput.substring(pos));

        return result.toString();

    }