Description
https://leetcode.com/problems/thousand-separator/
Given an integer n, add a dot (“.”) as the thousands separator and return it in string format.
Example 1:
Input: n = 987 Output: "987"
Example 2:
Input: n = 1234 Output: "1.234"
Example 3:
Input: n = 123456789 Output: "123.456.789"
Example 4:
Input: n = 0 Output: "0"
Constraints:
0 <= n < 2^31
Explanation
Convert the integer to string and add “.” on every 3 characters.
Python Solution
class Solution:
def thousandSeparator(self, n: int) -> str:
result = []
n_str = str(n)
for i, c in enumerate(n_str[::-1]):
if i != 0 and i % 3 == 0:
result.insert(0, ".")
result.insert(0, c)
return "".join(result)
- Time Complexity: O(N).
- Space Complexity: O(N).