Add : boj2668

Author: dgh03207

src/Baekjoon/java/gold/boj2668.java

@@ -0,0 +1,44 @@
+package Baekjoon.java.gold;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class boj2668 {
+    static int nums[],N,maxCnt;
+    static boolean[] checked;
+    static List<Integer> answer;
+    public static void main(String[] args) throws Exception{
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        N = Integer.parseInt(br.readLine());
+        nums = new int[N+1];
+
+        maxCnt=0;
+        for (int i = 1; i < N+1; i++) {
+            nums[i] = Integer.parseInt(br.readLine());
+        }
+        checked = new boolean[N+1];
+        answer = new ArrayList<Integer>();
+        for (int i = 1; i<=N; i++) {
+            checked[i] = true;
+            dfs(i,i);
+            checked[i] = false;
+        }
+        answer = answer.stream().sorted().distinct().collect(Collectors.toList());
+        System.out.println(answer.size());
+        for (int i = 0; i < answer.size(); i++) {
+            System.out.println(answer.get(i));
+        };
+    }
+
+    private static void dfs(int start,int now){
+        if(!checked[nums[now]]){
+            checked[nums[now]] = true;
+            dfs(start,nums[now]);
+            checked[nums[now]] = false;
+        }
+        if(nums[now]==start) answer.add(now);
+    }
+}