diff --git a/S2OJ/1024/1024.cpp b/S2OJ/1024/1024.cpp
new file mode 100644
index 00000000..a016b5a8
--- /dev/null
+++ b/S2OJ/1024/1024.cpp
@@ -0,0 +1,44 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, k, p, trie[10000005][2], size[10000005];
+char s[100005];
+bool a[100005];
+
+void calcsize(int u) {
+    if (trie[u][0]) calcsize(trie[u][0]);
+    if (trie[u][1]) calcsize(trie[u][1]);
+    size[u] += size[trie[u][0]] + size[trie[u][1]];
+}
+
+void print(int u, int k) {
+    if (u != 1 && k-- == 1) {
+        cout << endl;
+        exit(0);
+    }
+    if (size[trie[u][0]] >= k) {
+        cout << 0;
+        print(trie[u][0], k);
+    } else {
+        cout << 1;
+        print(trie[u][1], k - size[trie[u][0]]);
+    }
+}
+
+int main() {
+    cin >> n >> k >> s + 1;
+    for (int i = 1; i <= n; i++) {
+        a[i] = s[i] - '0';
+    }
+    p = 1;
+    for (int i = 1; i <= n; i++) {
+        int u = 1;
+        for (int j = i; j <= min(n, i + k - 1); j++) {
+            size[u = (trie[u][a[j]] ? trie[u][a[j]] : trie[u][a[j]] = ++p)] = 1;
+        }
+    }
+    calcsize(1);
+    print(1, k);
+    return 0;
+}