diff --git a/S2OJ/2/2.cpp b/S2OJ/2/2.cpp
new file mode 100644
index 00000000..3bd41c3e
--- /dev/null
+++ b/S2OJ/2/2.cpp
@@ -0,0 +1,41 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, nxt[300005], pre[300005], a[300005], cnt;
+vector<int> b[300005];
+
+int main() {
+    cin >> n;
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+        if (a[i] == -1) ++cnt;
+    }
+    for (int i = 1; i < cnt; i++) {
+        nxt[i] = i + 1;
+    }
+    nxt[cnt] = 1;
+    for (int i = 2; i <= cnt; i++) {
+        pre[i] = i - 1;
+    }
+    pre[1] = cnt;
+    int now = 1;
+    for (int i = 1; i <= n; i++) {
+        if (a[i] == -1) {
+            nxt[pre[now]] = nxt[now];
+            pre[nxt[now]] = pre[now];
+        } else {
+            b[now].push_back(a[i]);
+        }
+        now = nxt[now];
+    }
+    cout << cnt << endl;
+    for (int i = 1; i <= cnt; i++) {
+        cout << b[i].size() << ' ';
+        for (int j = 0; j < b[i].size(); ++j) {
+            cout << b[i][j] << ' ';
+        }
+        cout << endl;
+    }
+    return 0;
+}