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描述
You are given a phone number as a string number. number consists of digits, spaces ' ', and/or dashes '-'.
You would like to reformat the phone number in a certain manner. Firstly, remove all spaces and dashes. Then, group the digits from left to right into blocks of length 3 until there are 4 or fewer digits. The final digits are then grouped as follows:
- 2 digits: A single block of length 2.
- 3 digits: A single block of length 3.
- 4 digits: Two blocks of length 2 each.
The blocks are then joined by dashes. Notice that the reformatting process should never produce any blocks of length 1 and produce at most two blocks of length 2.
Return the phone number after formatting.
Example 1:
Input: number = "1-23-45 6"
Output: "123-456"
Explanation: The digits are "123456".
Step 1: There are more than 4 digits, so group the next 3 digits. The 1st block is "123".
Step 2: There are 3 digits remaining, so put them in a single block of length 3. The 2nd block is "456".
Joining the blocks gives "123-456".
Example 2:
Input: number = "123 4-567"
Output: "123-45-67"
Explanation: The digits are "1234567".
Step 1: There are more than 4 digits, so group the next 3 digits. The 1st block is "123".
Step 2: There are 4 digits left, so split them into two blocks of length 2. The blocks are "45" and "67".
Joining the blocks gives "123-45-67".
Example 3:
Input: number = "123 4-5678"
Output: "123-456-78"
Explanation: The digits are "12345678".
Step 1: The 1st block is "123".
Step 2: The 2nd block is "456".
Step 3: There are 2 digits left, so put them in a single block of length 2. The 3rd block is "78".
Joining the blocks gives "123-456-78".
Example 4:
Input: number = "12"
Output: "12"
Example 5:
Input: number = "--17-5 229 35-39475 "
Output: "175-229-353-94-75"
Note:
2 <= number.length <= 100
number consists of digits and the characters '-' and ' '.
There are at least two digits in number.
解析
根据题意，就是将先将 number 中的空格和 - 去掉，然后每 3 位分成一小块，用 - 连接起来，如果最后剩下三位或者两位数字，则直接用 - 连接在之前的字符串后面，如果剩下的是四位，则用两个两位数字和 - 连接在之前的字符串后面，最后返回用 - 连接好的字符串。
解答
class Solution(object):
def reformatNumber(self, number):
"""
:type number: str
:rtype: str
"""
number = number.replace(' ','').replace('-','')
def f(number, r):
if len(number)<=4:
if len(number)==2 or len(number)==3:
return r+number
else:
return r+number[:2]+'-'+number[2:]
r += number[:3] + '-'
return f(number[3:], r)
return f(number, '')
运行结果
Runtime: 16 ms, faster than 75.00% of Python online submissions for Reformat Phone Number.
Memory Usage: 13.5 MB, less than 37.50% of Python online submissions for Reformat Phone Number.
原题链接：leetcode.com/problems/re…
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