You are given a string num consisting of digits only.
Return the largest palindromic integer (in the form of a string) that can be formed using digits taken from num. It should not contain leading zeroes.
Notes:
Examples
Example 1
Input: num = "444947137"
Output: "7449447"
Explanation:
Use the digits "4449477" from "444947137" to form the palindromic integer "7449447".
It can be shown that "7449447" is the largest palindromic integer that can be formed.
Example 2
Input: num = "00009"
Output: "9"
Explanation:
It can be shown that "9" is the largest palindromic integer that can be formed.
Note that the integer returned should not contain leading zeroes.
Constraints
1 <= num.length <= 105
num consists of digits.
2384. Largest Palindromic Number
Medium
30 Points
Hash Table
String
Greedy
Counting
You are given a string num consisting of digits only.
Return the largest palindromic integer (in the form of a string) that can be formed using digits taken from num. It should not contain leading zeroes.
Notes:
Examples
Example 1
Input: num = "444947137"
Output: "7449447"
Explanation:
Use the digits "4449477" from "444947137" to form the palindromic integer "7449447".
It can be shown that "7449447" is the largest palindromic integer that can be formed.
Example 2
Input: num = "00009"
Output: "9"
Explanation:
It can be shown that "9" is the largest palindromic integer that can be formed.
Note that the integer returned should not contain leading zeroes.
Constraints
1 <= num.length <= 105
num consists of digits.
Largest Palindromic Number - Practice Coding | SlaveCode