class Solution:
    def summaryRanges(self, nums: list[int]) -> list[str]:
        if len(nums) == 0:
            return []
        rlt = []
        start = nums[0]
        end = start
        last = start
        for idx, ele in enumerate(nums[1:]):
            if ele == last + 1:
                end = ele
            else:
                rlt.append((start, end))
                start = ele
                end = ele
            last = ele
        rlt.append((start,end))
        str_rlt = []
        for ele in rlt:
            if ele[0] == ele[1]:
                str_rlt.append(f"{ele[0]}")
            else:
                str_rlt.append(f"{ele[0]}->{ele[1]}")
        return str_rlt

sol = Solution()
print(sol.summaryRanges([0,1,2,4,5,7]))
print(sol.summaryRanges([0,2,3,4,6,8,9]))