Watch 10 video solutions for Largest Palindromic Number, a medium level problem involving Hash Table, String, Greedy. This walkthrough by NeetCode has 629,143 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
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:
num, but you must use at least one digit.
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 <= 105num consists of digits.