[筆記] Leetcode - 1903. Largest Odd Number in String

You are given a string num, representing a large integer. Return the largest-valued odd integer (as a string) that is a non-empty substring of num, or an empty string “” if no odd integer exists.

A substring is a contiguous sequence of characters within a string.

Example 1:

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Input: num = "52"
Output: "5"
Explanation: The only non-empty substrings are "5", "2", and "52". "5" is the only odd number.

Example 2:

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Input: num = "4206"
Output: ""
Explanation: There are no odd numbers in "4206".

Example 3:

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Input: num = "35427"
Output: "35427"
Explanation: "35427" is already an odd number.

class Solution:
    def largestOddNumber(self, num: str) -> str:
        for i in range(len(num) - 1, -1, -1):

            if int(num[i]) % 2:
                return num[:i + 1]

        return ''