diff --git "a/JHLEE325/202509/25 BOJ G5 \354\210\253\354\236\220\352\263\240\353\245\264\352\270\260.md" "b/JHLEE325/202509/25 BOJ G5 \354\210\253\354\236\220\352\263\240\353\245\264\352\270\260.md" new file mode 100644 index 00000000..555acfc3 --- /dev/null +++ "b/JHLEE325/202509/25 BOJ G5 \354\210\253\354\236\220\352\263\240\353\245\264\352\270\260.md" @@ -0,0 +1,44 @@ +```java +import java.io.*; +import java.util.*; + +public class Main { + static int n; + static int[] arr; + static boolean[] visited; + static Set result = new TreeSet<>(); + + public static void main(String[] args) throws IOException { + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + StringTokenizer st; + StringBuilder sb = new StringBuilder(); + + n = Integer.parseInt(br.readLine()); + + arr = new int[n +1]; + for (int i = 1; i <= n; i++) { + arr[i] = Integer.parseInt(br.readLine()); + } + + for (int i = 1; i <= n; i++) { + visited = new boolean[n +1]; + dfs(i, i); + } + + sb.append(result.size()).append("\n"); + for (int x : result) sb.append(x).append("\n"); + System.out.print(sb); + } + + static void dfs(int start, int cur) { + if (!visited[cur]) { + visited[cur] = true; + dfs(start, arr[cur]); + } else { + if (cur == start) { + result.add(cur); + } + } + } +} +```