diff --git a/debug.js b/debug.js
index e69de29..ebf23d8 100644
--- a/debug.js
+++ b/debug.js
@@ -0,0 +1,2 @@
+//[ 4, 1, 4, 5, 3 ] [ 8, 8, 10, 9, 12 ] 33
+console.log(4);
diff --git a/hackerrank/contacts.ts b/hackerrank/contacts.ts
new file mode 100644
index 0000000..37fbedd
--- /dev/null
+++ b/hackerrank/contacts.ts
@@ -0,0 +1,41 @@
+// wrong solution
+function countContacts(queries: string[][]): number[] {
+  let contacts: string[] = [],
+    result: number[] = [];
+
+  if (queries.length < 2) {
+    return [0];
+  }
+
+  for (let arr of queries) {
+    let action = arr[0],
+      value = arr[1];
+
+    switch (action) {
+      case "add": {
+        contacts.push(value);
+        break;
+      }
+      case "find": {
+        const filtered = contacts.filter((contact) =>
+          contact.startsWith(value)
+        );
+        result.push(filtered.length);
+        break;
+      }
+      default: {
+        break;
+      }
+    }
+  }
+
+  return result;
+}
+
+const input = [
+  ["add", "hack"],
+  ["add", "hackerrank"],
+  ["find", "hac"],
+  ["find", "hak"],
+];
+console.log(countContacts(input));