[백준] 23305 수강변경 - Greedy / Java

• 문제 링크

23305번: 수강변경

 

• 풀이 코드

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int n = read();
        int[] arr = new int[1000001];
        for (int i = 0; i < n; i++) arr[read()]++;

        int cnt = 0, i;
        while (n-- > 0) {
            if (arr[i = read()] > 0) arr[i]--;
            else cnt++;
        }

        bw.write(String.valueOf(cnt));
        bw.flush();
    }

    private static int read() throws IOException {
        int c, n = System.in.read() & 15;
        while ((c = System.in.read()) > 32) n = (n << 3) + (n << 1) + (c & 15);

        return n;
    }

}