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"
Constraints:
- 2 <= number.length <= 100
- number consists of digits and the characters ‘-‘ and ‘ ‘.
- There are at least two digits in number.
Solution in python:
class Solution:
def reformatNumber(self, number: str) -> str:
alist = []
for char in number:
if char.isdigit():
alist.append(char)
result = ""
i = 0
length = len(alist)
# print(alist)
while length-i > 0:
if length-i > 4:
temp = ''.join(alist[i:i+3]) + "-"
result += temp
i += 3
elif length-i == 4:
temp = ''.join(alist[i:i+2]) + "-" + ''.join(alist[i+2:i+4])
result += temp
i += 4
else:
result += ''.join(alist[i:])
break
return result
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