How do I find Consecutive Letters?

[kiraz cevik]

Sorted String İnput: 1, 2, 2A, 2B, 2C, 3, 3A, 4, 5, 6, 32C, 32D, 50, 51/1, 51/2, 60, 61, 62, 200-2E, 200-2F, 200-2G, 200-2H, 201C, 201/21P, 201/21R, 201/21S,300,300A,301-2A, 542/2K, 542/2L,583-1, 583-585D, 583-585E, 605, 605A, 605B,605C 800A.
Question is about merging consecutive values into a range. E.g.4,5,6 =[4-6] , 2A, 2B, 2C are consecutive values, so range is 2[A-C]. No other values can be in a range.
• General pattern: number[chars][A-Z]
If chars is present, then they have to be equals() to be in a sequence. If the trailing letter is present, they have to be consecutive to have a sequence
A sequence is then abbreviated using: first + "-" + last
51/1, 52/1, 53/1 ==> not merged
51/1A, 51/1B, 51/1C ==> 51/1[A-C]
51/1A, 52/1B, 53/1C ==> [51-53]/1[A-C]
It should be listed as follows.

output:
1  
2
2[A-C]
3
3A
[4-6]
32[C-D]
50
51/1
51/2
[60-62]
200-2[E-H]
201C
201/21[P-S]
300
300A
301-2A
542/2[K-L]
583-1
583-585[D-E]
605
605[A-C]
800A

public static void main(String[] args) {
String input="1, 2, 2A, 2B, 2C, 3, 3A, 4, 5, 6, 32C, 32D, 50, 51/1, 51/2, 60, 61, 62, 200-2E, 200-2F, 200-2G, 200-2H, 201C, 201/21P, 201/21R, 201/21S,300,300A,301-2A, 542/2K, 542/2L,583-1, 583-585D, 583-585E, 605, 605A, 605B,605C 800A";
 List<String> items = Arrays.asList(input.split("\\s*,\\s*"));
   System.out.println("items: " + items);
 
List<String> merged = mergeRanges(items);
System.out.println("merged:  " + merged);
}
private static List<String> mergeRanges(List<String> items) {
      List<String> merged = new ArrayList<>();
 
      int startNum = Integer.MIN_VALUE;
      int lastNum = Integer.MIN_VALUE;
      boolean inRange = false;
 
      for (String s : items) {
          if (isInteger(s)) {
              int currentNum = Integer.parseInt(s);
 
              if (!inRange) {
                  inRange = true;
                  startNum = currentNum;
                  lastNum = currentNum;
              } else if (currentNum == lastNum + 1) {
                  lastNum = currentNum;
              } else {
                  addRange(merged, startNum, lastNum);
                  startNum = currentNum;
                  lastNum = currentNum;
              }
          } else {
              if (inRange) {
                  addRange(merged, startNum, lastNum);
                  inRange = false;
              }
 
              merged.add(s);
          }
      }
 
       if (inRange) {
 
       addRange(merged, startNum, lastNum);
       }
      return merged;
  }
 
  private static boolean isInteger(String strlist) {
      return strlist.matches("\\d+");
  }
 
  private static void addRange(List<String> merged, int startNum, int lastNum) {
      if (lastNum - startNum >= 2) {
          merged.add("[" + startNum + "-" + lastNum + "]");
      } else {
          for (int i = startNum; i <=lastNum; i++) {
              merged.add(Integer.toString(i));
          } } }}

output= merged: [1, 2, 2A, 2B, 2C, 3, 3A, [4-6], 32C, 32D, 50, 51/1, 51/2, [60-62], 200-2E, 200-2F, 200-2G, 200-2H, 201C, 201/21P, 201/21R, 201/21S, 300,300A,301-2A,542/2K, 542/2L,583-1, 583-585D, 583-585E, 605, 605A, 605B,605C 800A]

I'm waiting for your help.thanks.

[Martin Vashko]

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