[java] 백준 10845 : 큐, 10828 : 스택

큐

문제

https://www.acmicpc.net/problem/10845

10845번: 큐

 

풀이

scanner로 하니 시간초과가 발생하여 bufferedReader사용하니 해결됨

 

코드

package main;
import java.io.*;
import java.util.*;

//큐는 선입선출
public class Main {
	static Queue<Integer> q;
	
	public static void main(String[] args) throws IOException {
		q = new LinkedList<>(); 
		
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		int n = Integer.parseInt(st.nextToken());
		String x;
		int pn=0;
		for(int i=0; i<n; i++) {
			st = new StringTokenizer(br.readLine());
			x = st.nextToken();
			if(x.equals("push")) {
				pn = Integer.parseInt(st.nextToken());
				q.add(pn);
			}else if(x.equals("pop")) {
				System.out.println(q.isEmpty()? -1: q.poll());
			}else if(x.equals("size")) {
				System.out.println(q.size());
			}
			else if(x.equals("empty")){
				System.out.println(q.isEmpty()? 1: 0);
			}else if(x.equals("front")) {
				System.out.println(q.isEmpty()? -1: q.peek());
			}
			else if(x.equals("back")) {
				System.out.println(q.isEmpty()? -1: pn);
			}
			
		}
		
	}
	
	

}

 

 

스택

문제

https://www.acmicpc.net/problem/10828

10828번: 스택

 

코드

import java.io.*;
import java.util.*;


public class Main {
	static Stack<Integer> stack;
	
	public static void main(String[] args) throws IOException {
		stack = new Stack<Integer>();
		
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		int n = Integer.parseInt(st.nextToken());
		String x;
		int pn=0;
		for(int i=0; i<n; i++) {
			st = new StringTokenizer(br.readLine());
			x = st.nextToken();
			if(x.equals("push")) {
				pn = Integer.parseInt(st.nextToken());
				stack.add(pn);
			}else if(x.equals("pop")) {
				System.out.println(stack.isEmpty()? -1: stack.pop());
			}else if(x.equals("size")) {
				System.out.println(stack.size());
			}
			else if(x.equals("empty")){
				System.out.println(stack.isEmpty()? 1: 0);
			}
			else if(x.equals("top")) {
				System.out.println(stack.isEmpty()? -1: stack.peek());
			}
			
		}
		
	}
	
	

}