How to get the least number after deleting k digits from the input number

Question

For example, if the input number is 24635, the least number is 23 after deleting any 3 digits.

It\'s not the same as taking the two smalles

Answer 1

The idea is to traverse through the string from the beginning and remove the first digit which is greater than the digit following it. If no such digit exists, remove the last digit.

    class Solution {
    private:
        void removeOneDigit(string& s){
            for(int i=0; i