README_EN.md

1903. Largest Odd Number in String

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Description

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.

Solutions

Python3

class Solution:
    def largestOddNumber(self, num: str) -> str:
        for i in range(len(num) - 1, -1, -1):
            if (int(num[i]) & 1) == 1:
                return num[: i + 1]
        return ''

Java

class Solution {
    public String largestOddNumber(String num) {
        for (int i = num.length() - 1; i >= 0; --i) {
            int c = num.charAt(i) - '0';
            if ((c & 1) == 1) {
                return num.substring(0, i + 1);
            }
        }
        return "";
    }
}

JavaScript

/**
 * @param {string} num
 * @return {string}
 */
var largestOddNumber = function (num) {
    let n = num.length;
    for (let j = n - 1; j >= 0; j--) {
        if (num.charAt(j) & (1 == 1)) {
            return num.slice(0, j + 1);
        }
    }
    return '';
};

C++

class Solution {
public:
    string largestOddNumber(string num) {
        for (int i = num.size() - 1; i >= 0; --i) {
            int c = num[i] - '0';
            if ((c & 1) == 1) {
                return num.substr(0, i + 1);
            }
        }
        return "";
    }
};

Go

func largestOddNumber(num string) string {
	for i := len(num) - 1; i >= 0; i-- {
		c := num[i] - '0'
		if (c & 1) == 1 {
			return num[:i+1]
		}
	}
	return ""
}

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