# 給一個Java整數list，印出list有連續整數的數字

public class Test {

    public static void main(String[] args) {
      List<Integer> list = Arrays.asList(0,1,2,5,7,8,9,9,10,11,15);
      
      List<String> resultList =  findRanges(list);
      
      for(String i : resultList) {
          System.out.print(i+" ");
      }
    }

    private static List<String> findRanges(List<Integer> list){
        List<String> resultList = new ArrayList<String>();
        for(int i=0;i<list.size();i++) {
            StringBuffer sb = new StringBuffer();
            sb.append(list.get(i));
            
            for(int j=i;j<list.size()-1;j++) {
                if(list.get(j+1)-list.get(j) <= 1) {
                    
                }else {
                    break;
                }
                i=j+1;
            }
            sb.append("->");
            sb.append(list.get(i));
            
            if(i != list.size()-1) {
                sb.append(" , ");
            }
            
            resultList.add(sb.toString());
        }
        return resultList;
    }

}

console:

0->2 ,  5->5 ,  7->11 ,  15->15