228. Summary Ranges

class Solution {
    public List<String> summaryRanges(int[] nums) {
        int n = nums.length, i = 0, j = 0;
        List<String> list = new ArrayList<>();
        while(i < n)
        {
            int step = 0;
            while(j < n && nums[i] + step == nums[j])
            {
                j++;
                step++;
            }
            list.add(toStr(nums[i], nums[j - 1]));
            i = j;
        }
        return list;
    }

    String toStr(int a, int b)
    {
        if(a == b) return "" + a;
        return a + "->" + b;
    }
}