diff --git a/1415. The k-th Lexicographical String of All Happy Strings of Length n b/1415. The k-th Lexicographical String of All Happy Strings of Length n
new file mode 100644
index 0000000..291ca4c
--- /dev/null
+++ b/1415. The k-th Lexicographical String of All Happy Strings of Length n	
@@ -0,0 +1,24 @@
+class Solution {
+public:
+    string s = "abc", ans;
+    void backtrack(string cur, int &n, int &k, int &count)
+    {
+        if(count == k) return;
+        if(cur.size() == n)
+        {
+            ans = cur, count += 1;
+            return;
+        }
+        for(auto ch : s)
+        {
+            if(cur.size() and ch == cur.back()) continue;
+            backtrack(cur + ch, n, k, count);
+        }
+    }
+    string getHappyString(int n, int k) 
+    {
+        int count = 0;
+        backtrack("", n, k, count);
+        return count == k ? ans : "";
+    }
+};