largest-odd-number-in-string

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1903. Largest Odd Number in String (Easy)

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:

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

Example 2:

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

Example 3:

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

 

Constraints:

• 1 <= num.length <= 105
• num only consists of digits and does not contain any leading zeros.

Related Topics

[Math] [String] [Greedy]

Hints

Hint 1

In what order should you iterate through the digits?

Hint 2

If an odd number exists, where must the number start from?