動機
雖說是水題,但有用到一個python特點
Problem
You are given a sorted unique integer array nums
.
Return the smallest sorted list of ranges that cover all the numbers in the array exactly. That is, each element of nums
is covered by exactly one of the ranges, and there is no integer x
such that x
is in one of the ranges but not in nums
.
Each range [a,b]
in the list should be output as:
a->b
ifa != b
a
ifa == b
Example 1:
Input: nums = [0,1,2,4,5,7]Output: [0->2,4->5,7]Explanation: The ranges are:[0,2] --> 0->2[4,5] --> 4->5[7,7] --> 7
Example 2:
Input: nums = [0,2,3,4,6,8,9]Output: [0,2->4,6,8->9]Explanation: The ranges are:[0,0] --> 0[2,4] --> 2->4[6,6] --> 6[8,9] --> 8->9
Example 3:
Input: nums = []Output: []
Example 4:
Input: nums = [-1]Output: [-1]
Example 5:
Input: nums = [0]Output: [0]
Constraints:
0 <= nums.length <= 20
-231 <= nums[i] <= 231 - 1
- All the values of
nums
are unique. nums
is sorted in ascending order.
Sol
forloop的b會蓋到原本的b!!
class Solution:
def summaryRanges(self, nums: List[int]) -> List[str]:
if not nums:
return []
ret = []
a,b = 0,0
for b in range(1,len(nums)):
if nums[b-1]+1 != nums[b]:
if a != b-1:
ret.append(f'{nums[a]}->{nums[b-1]}')
else:
ret.append(f'{nums[a]}')
a = b
if a != b:
ret.append(f'{nums[a]}->{nums[b]}')
else:
ret.append(f'{nums[a]}')
return ret