Merge pull request #1669 from Abhinavcode13/patch-32

Create Count.go

Author: akgmage

Math/Count.go

@@ -0,0 +1,20 @@
+class Solution {
+public:
+    int countNumbersWithUniqueDigits(int n) {
+        if (n == 0) {
+            return 1; // There's only one number with 0 digits, which is 0.
+        }
+        
+        int result = 10; // For n = 1, there are 10 numbers with unique digits (0-9).
+        int uniqueDigits = 9;
+        int availableDigits = 9;
+        
+        for (int i = 2; i <= n && availableDigits > 0; i++) {
+            uniqueDigits *= availableDigits;
+            result += uniqueDigits;
+            availableDigits--;
+        }
+        
+        return result;
+    }
+};