import java.util.ArrayList;
import java.util.List;

/**
 * BracketExpension
*/
public class BracketExpension {
  // You are given a string expression which consists of several comma separated
  // tokens
  // enclosed within opening ('{') and closing ('}') curly braces.
  // The string expression might or might not have a prefix before opening curly
  // brace('{') and
  // a suffix after closing curly brace ('}').
  // You have to return a list of strings as output for each comma separated item
  // as shown below in the examples.
  //
  // Example 1:
  // Input = "/2022/{jan,feb,march}/report"
  // Output = "/2022/jan/report"
  // "/2022/feb/report"
  // "/2022/march/report"
  //
  // Example 2:
  // Input = "over{crowd,eager,bold,fond}ness"
  // Output = "overcrowdness"
  // "overeagerness"
  // "overboldness"
  // "overfondness"
  //
  // Example 3:
  // Input = "read.txt{,.bak}"
  // Output = "read.txt"
  // "read.txt.bak"

  public static void main(String[] args) {
    String tokens = "over{crowd,eager,bold,fond}ness";
    String tokeneez = "/2022/{jan,feb,march}/report";
    List<String> options = TokensListed(tokeneez);
    for (int i = 0; i < options.size(); i++) {
      System.out.println(options.get(i));
    }
  }

  public static List<String> TokensListed(String str) {
    List<String> ans = new ArrayList<>();
    // let's find the starting and the ending of the indecies of the curly braces;
    int startIndex = str.indexOf("{");
    int endIndex = str.indexOf("}");

    if (startIndex == -1 || endIndex == -1 || startIndex > endIndex) {
      ans.add(str);
      return ans;
    }

    // Extract the prefix, suffix and the options;
    String prefix = str.substring(0, startIndex);
    String suffix = str.substring(endIndex + 1);
    String options = str.substring(startIndex + 1, endIndex);

    // Split the options by comma
    String[] tokens = options.split(",");
    for (String token : tokens) {
      ans.add(prefix + token + suffix);
    }
    return ans;
  }
}