[문제 풀이] 백준 10845 큐 (배열로 구현한 큐)

import java.util.Scanner; public class queue { static int Queue[]; static int rear; public static void main(String args[]){ init(); int N; Scanner sc = new Scanner(System.in); N=sc.nextInt(); Queue= new int[N]; //push(1); for(int i=0; i<N;i++){ String s; s=sc.next(); if(s.equals("push")){ int t=sc.nextInt(); push(t); } else if(s.equals("pop")){ System.out.println(pop()); } else if(s.equals("empty")){ System.out.println(empty()); } else if(s.equals("size")){ System.out.println(size()); } else if(s.equals("front")){ System.out.println(front()); } else if(s.equals("back")){ System.out.println(back()); } } } static void init(){ rear=-1; } static int empty(){ if(rear==-1) return 1; return 0; } static void push(int data){ rear++; Queue[rear]=data; //System.out.println(data); } static int pop(){ int tmp=Queue[0]; if(rear<0) return -1; for(int i=0;i<rear;i++){ Queue[i]=Queue[i+1]; } rear--; return tmp; } static int size(){ if(rear<0) return 0; return rear+1; } static int front(){ if(empty()==1) return -1; return Queue[0]; } static int back(){ if(empty()==1 || rear == -1) return -1; return Queue[rear]; } }