programmers_큰 수 만들기_java

https://school.programmers.co.kr/learn/courses/30/lessons/42883

프로그래머스

import java.util.*;

class Solution {
    public String solution(String number, int k) {
        String answer = "";
        
        int numberLength = number.length();
        Stack<Integer> stack = new Stack<>();
        
        for(int i = 0; i< numberLength; i++){
            
            while(k>0 && !stack.isEmpty()){
                if(stack.peek() < number.charAt(i)-'0'){
                    stack.pop();
                    k--;
                }else{
                    break;
                }
            }
            stack.push(number.charAt(i)-'0');            
        }
        
        StringBuilder sb = new StringBuilder();        
        while(!stack.isEmpty()){
            if(stack.size() > numberLength - k){
                stack.pop();
            }else{                
                sb.insert(0, stack.pop());  
            }          
        }
        answer = sb.toString();
        return answer;
    }
}