Search a string splitted into different list positions and get the starting and ending position

Question

i have a string splitted into different positions in a list e.g.,

List<String> str = new ArrayList<String>();
str.add("This is a ");
str.add("[{searched");
str.add("_placeholder}]");
str.add(" in this string.");

I want to search "[{searched_string}]" in a list and want to know which is the starting and the ending position of "[{searched_string}]" in the list. E.g., in the above list the starting position of the "[{searched_string}]" is 1 and 2 respectively.

Can someone please guide me with any algorithm that can return me the starting and the ending position of the string being searched?

Answer 1

Would something like the below code work? It is not very efficient, but seems to work. For the list in the question, with the searched string as searched_placeholder, it returns a start index of 1 and end index of 2.

      List<String> str = new ArrayList<String>();
      str.add("This is a ");
      str.add("[{searched");
      str.add("_placeholder}]");
      str.add(" in this string.");
      
      String searchString = "searched_placeholder";
      StringBuilder completeString = new StringBuilder();
      int endIndex = 0;
      int startIndex = 0;
      
      for (int index = 0; index < str.size(); index++) {
          completeString.append(str.get(index));
          
          if (completeString.indexOf(searchString) != -1) {
              endIndex = index;
              break;
          }
      }
      
      for (int index = 0; index <= endIndex; index++) {
          completeString.replace(0, str.get(index).length(), "");
          
          if (completeString.indexOf(searchString) == -1) {
              startIndex = index;
              break;
          }
      }
      
      System.out.println("Start index: " + startIndex + ", End index: " + endIndex);