Summary Ranges

Given a sorted integer array without duplicates, return the summary of its ranges.

Example 1:

Input:  [0,1,2,4,5,7]
Output: ["0->2","4->5","7"]
Explanation: 0,1,2 form a continuous range; 4,5 form a continuous range.

Example 2:

Input:  [0,2,3,4,6,8,9]
Output: ["0","2->4","6","8->9"]
Explanation: 2,3,4 form a continuous range; 8,9 form a continuous range.

class Solution {
    public List<String> summaryRanges(int[] nums) {
        List<String> list = new ArrayList();
        if (nums.length == 1) {
            list.add(nums[0] + "");
            return list;
        }
        for (int i = 0; i < nums.length; i++) {
            int a = nums[i];
            while (i + 1 < nums.length && nums[i] + 1 == nums[i + 1])
                i++;
            if (a != nums[i])
                list.add(a + "->" + nums[i]);
            else
                list.add(a + "");
        }
        return list;
    }
}