diff --git a/AcWing/800/800.cpp b/AcWing/800/800.cpp
new file mode 100644
index 00000000..767afcb5
--- /dev/null
+++ b/AcWing/800/800.cpp
@@ -0,0 +1,27 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+#define endl '\n'
+
+const int N = 100005;
+
+int n, m, x, a[N], b[N];
+
+int main() {
+    cin >> n >> m >> x;
+    for (int i = 0; i < n; i++) {
+        cin >> a[i];
+    }
+    for (int i = 0; i < m; i++) {
+        cin >> b[i];
+    }
+    for (int i = 0, j = m - 1; i < n; i++) {
+        while (a[i] + b[j] > x) j--;
+        if (a[i] + b[j] == x) {
+            cout << i << ' ' << j << endl;
+            exit(0);
+        }
+    }
+    return 0;
+}