diff --git a/InSange/DFS/2668.cpp b/InSange/DFS/2668.cpp
new file mode 100644
index 0000000..e6ea5a5
--- /dev/null
+++ b/InSange/DFS/2668.cpp
@@ -0,0 +1,60 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+int N, num;
+vector<bool> visited;
+vector<int> v;
+vector<int> answer;
+
+void DFS(int cur, int start)
+{
+	if (visited[cur] == true)
+	{
+		if (start == cur) answer.push_back(start);
+		return;
+	}
+
+	visited[cur] = true;
+	DFS(v[cur], start);
+	visited[cur] = false;
+}
+
+void Solve()
+{
+	cin >> N;
+
+	N += 1;
+	visited.assign(N, false);
+	v.assign(N, 0);
+
+	for (int i = 1; i < N; i++)
+	{
+		cin >> v[i];
+	}
+
+	for (int i = 1; i < N; i++)
+	{
+		DFS(i, i);
+	}
+
+	int asize = answer.size();
+	cout << asize << "\n";
+
+	for (int i = 0; i < asize; i++)
+	{
+		cout << answer[i] << "\n";
+	}
+}
+
+int main()
+{
+	cin.tie(nullptr);
+	ios::sync_with_stdio(false);
+
+	Solve();
+
+	return 0;
+}
\ No newline at end of file
diff --git a/InSange/README.md b/InSange/README.md
index 358e16c..a29d500 100644
--- a/InSange/README.md
+++ b/InSange/README.md
@@ -12,4 +12,5 @@
 | 8차시 | 2024.04.09 |  투 포인터  | [두 용액](https://www.acmicpc.net/problem/2470)  | [#8](https://github.com/AlgoLeadMe/AlgoLeadMe-8/pull/32)]
 | 9차시 | 2024.04.12 |  힙  | [Top K Frequent Words](https://leetcode.com/submissions/detail/1180988760/)  | [#9](https://github.com/AlgoLeadMe/AlgoLeadMe-8/pull/28)]
 | 10차시 | 2024.05.02 |  스택  | [오아시스 재결합](https://www.acmicpc.net/problem/3015)  | [#10](https://github.com/AlgoLeadMe/AlgoLeadMe-8/pull/40)]
+| 11차시 | 2024.05.02 |  DFS  | [숫자고르기](https://www.acmicpc.net/problem/2668)  | [#11](https://github.com/AlgoLeadMe/AlgoLeadMe-8/pull/41)]
 ---