Delete Digits

Delete Digits

16%

Accepted

Given string A representative a positive integer which has N digits, remove any k digits of the number, the remaining digits are arranged according to the original order to become a new positive integer.

Find the smallest integer after remove k digits.

N <= 240 and k <= N,

Have you met this question in a real interview? 

Yes

Example

Given an integer A = "178542", k = 4

return a string "12"

public class Solution {

    /**

     *@param A: A positive integer which has N digits, A is a string.

     *@param k: Remove k digits.

     *@return: A string

     */

    public String DeleteDigits(String A, int k) {

        // write your code here

        

        for(int i = 1; i < A.length() && k > 0;){

            if(A.charAt(i) < A.charAt(i-1)){

                A = A.substring(0, i-1) + A.substring(i);

                k--;

                if(i > 1)

                    i--;

            } else i++;

        }

       int beg = 0;

       for(int i = 0 ; i < A.length(); i++){

           if(A.charAt(i) == '0'){

               beg++;

           } else break;

       }

        

        return A.substring(beg, A.length() - k);

    }

}