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## Problem

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.


## Code

class Solution {
public List<String> summaryRanges(int[] nums) {
List<String> res = new ArrayList<>();
if(nums == null || nums.length == 0) return res;

for(int i = 0; i < nums.length; i++){
int num = nums[i];
while(i < nums.length - 1 && nums[i] + 1 == nums[i + 1]){
i++;
}

// 是一个范围
if(num != nums[i]){
// 是一个数字
} else {
}
}

return res;
}
}

class Solution:
def summaryRanges(self, nums: List[int]) -> List[str]:
if not nums:
return []

res = []
start = nums[0]

for i in range(1, len(nums)):
if  nums[i] == nums[i - 1] + 1:
continue

if  start == nums[i - 1]:
res.append(str(start))
else:
res.append(str(start) + "->" + str(nums[i - 1]))

start = nums[i]

if nums[-1] == start:
res.append(str(nums[-1]))
else:
res.append(str(start) + "->" + str(nums[-1]))

return res