Summary Ranges

public class Solution {    public List<String> summaryRanges(int[] nums) {        //首尾问题，考虑使用双指针。 Two Pointers        List<String> result = new ArrayList<String>();        if (nums == null || nums.length == 0) {            return result;        }        int start = 0;        int end = 0;        while (end < nums.length) {            if (end + 1 < nums.length && nums[end + 1] == nums[end] + 1) {                end++;            } else {                if (start == end) {                    result.add(Integer.toString(nums[start]));                } else {                    String str = nums[start] + "->" + nums[end];                    result.add(str);                }                end++;                start = end;            }        }        return result;    }}