알고리즘입문(Java) - Stack,Queue 4.후위식 연산(postfix)

 

(풀이)

import java.util.*;
class Main {
    public int solution(String str){
        int answer=0;
        Stack<Integer> stack = new Stack<>();
        for(char x : str.toCharArray()){
            if(Character.isDigit(x)){
                stack.push(x-48);
            }
            else{
                int rt=stack.pop();
                int lt=stack.pop();
                if(x=='+') stack.push(lt+rt);
                else if(x=='-') stack.push(lt-rt);
                else if(x=='*') stack.push(lt*rt);
                else if(x=='/') stack.push(lt/rt);
            }
        }
        answer=stack.get(0);
        return answer;
    }
    public static void main(String[] args){
        Main T = new Main();
        Scanner kb = new Scanner(System.in);
        String str=kb.next();
        System.out.println(T.solution(str));
    }
}