package Leetcode;

import java.util.Stack;

public class RemoveKDigits

{

public static void main( String[] args )

{

RemoveKDigits obj = new RemoveKDigits();

System.out.println( obj.removeKdigits( "9", 1 ) );

}

public String removeKdigits(String num, int k) {

int count=k;

Stack<Integer> stack = new Stack();

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

{

int n = num.charAt(i)-'0';

while(!stack.isEmpty() && n<stack.peek() && count>0)

{

stack.pop();

count--;

}

stack.push(n);

}

while(count>0)

{

stack.pop();

count--;

}

StringBuilder result = new StringBuilder();

while(!stack.isEmpty())

{

result.append(stack.pop());

}

result.reverse();

while(result.length()>1 && result.charAt(0)=='0')

{

result.deleteCharAt(0);

}

if(result.length()==0)

result.append( "0");

return result.toString();

}

}