[백준] 31409 착신 전환 소동 - Graph Theory / Java

• 문제 링크

31409번: 착신 전환 소동

 

• 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));
        StringBuilder sb = new StringBuilder();

        int n = read(), cnt = 0;
        for (int i = 1; i <= n; i++) {
            int a = read();
            if (a == i) {
                a = a == n ? 1 : n;
                cnt++;
            }
            sb.append(a).append(" ");
        }

        bw.write(cnt + "\n" + sb);
        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;
    }

}