🟩 [백준] [Java] [Silver2] 1874번_스택 수열

문제

https://www.acmicpc.net/problem/1874

1874번: 스택 수열

풀이

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;

public class 스택수열 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb = new StringBuilder();

        Stack<Integer> stack = new Stack<>();

        int n = Integer.parseInt(br.readLine());

        int start = 0;

        while(n-- > 0){
            int value = Integer.parseInt(br.readLine());

            if(value > start){
                for(int i=start+1; i<=value; i++){
                    stack.push(i);
                    sb.append('+').append('\n');
                }
                start = value;
            }

            else if(stack.peek() != value){
                System.out.println("NO");
                return;
            }

            stack.pop();
            sb.append("-").append("\n");
        }

        System.out.println(sb);
    }
}