2710. Remove Trailing Zeros From a String

Problem

Given a positive integer num represented as a string, return **the integer *num* without trailing zeros as a string**.

Example 1:

Input: num = "51230100"
Output: "512301"
Explanation: Integer "51230100" has 2 trailing zeros, we remove them and return integer "512301".

Example 2:

Input: num = "123"
Output: "123"
Explanation: Integer "123" has no trailing zeros, we return integer "123".

Constraints:

• 1 <= num.length <= 1000
• num consists of only digits.
• num doesn't have any leading zeros.

Solution (Java)

class Solution {
    public String removeTrailingZeros(String num) {
        int len = num.length();
        while (--len >= 0) {
            if (num.charAt(len) != '0') break;
        }
        return num.substring(0, ++len);
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).