[백준] 차집합 1822 - JAVA

문제

https://www.acmicpc.net/problem/1822

1822번: 차집합

 

코드

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

public class Main {
	
	public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int n = Integer.parseInt(st.nextToken());
		int m = Integer.parseInt(st.nextToken());
				
		long arrA [] = new long [n];
		long arrB [] = new long [m];
		
		st = new StringTokenizer(br.readLine());
		for(int i=0;i<n;i++) {
			arrA[i] = Integer.parseInt(st.nextToken());
		}
		
		st = new StringTokenizer(br.readLine());
		for(int i=0;i<m;i++) {
			arrB[i] = Integer.parseInt(st.nextToken());
		}
		
		Arrays.sort(arrA);
		Arrays.sort(arrB);
		
		int a = 0;
		int b = 0;
		
		ArrayList<Long> result = new ArrayList<>();
		
		while(a < n) {
			if(b < m) {
				if(arrA[a] < arrB[b]) {
					result.add(arrA[a]);
					a++;
				}
				else if(arrA[a] > arrB[b]) {
					b++;
				}
				else {
					a++;
					b++;
				}	
			}
			else {
				result.add(arrA[a++]);
			}
		}
		
		System.out.println(result.size());
		for(int i=0;i<result.size();i++) {
			System.out.print(result.get(i)+" ");
		}		
		
	}
}