Fixed file naming conflict of the smallest subset with greater sum and added solution for problem no. 1415 leetcode which was not earlier in the list.

1415-The-k-th-Lexicographical-String-of-All-Happy-Strings-of-Length-n/1415-The-k-th-Lexicographical-String-of-All-Happy-Strings-of-Length-n.java

@@ -0,0 +1,41 @@
+class Solution {
+    // List to store all happy strings
+    List<String> list = new ArrayList<>();
+
+    // Method to get the k-th happy string of length n
+    public String getHappyString(int n, int k) {
+        char[] chr = {'a', 'b', 'c'};
+
+        // Generate all happy strings of length n
+        solve(chr, n, new StringBuilder());
+
+        // Sort the list of happy strings lexicographically
+        Collections.sort(list);
+
+        // Return the k-th happy string if it exists, otherwise return an empty string
+        return list.size() < k ? "" : list.get(k - 1);
+    }
+
+    // Recursive method to generate happy strings
+    void solve(char[] chr, int n, StringBuilder sb) {
+        // If the current string length equals n, add it to the list
+        if (n == sb.length()) {
+            list.add(sb.toString());
+            return;
+        }
+
+        // Iterate through each character in chr array
+        for (int i = 0; i < chr.length; i++) {
+            // Skip if the current character is the same as the last character in the string
+            if (sb.length() > 0 && chr[i] == sb.charAt(sb.length() - 1)) continue;
+
+            // Append the current character to the string
+            sb.append(chr[i]);
+            // Recursively generate the next character
+            solve(chr, n, sb);
+            // Remove the last character to backtrack
+            sb.setLength(sb.length() - 1);
+        }
+    }
+}
+