diff --git a/leetcode/66.py b/leetcode/66.py
new file mode 100644
index 0000000..b57fec6
--- /dev/null
+++ b/leetcode/66.py
@@ -0,0 +1,22 @@
+"""You are given a large integer represented as an integer array digits, 
+where each digits[i] is the ith digit of the integer. 
+The digits are ordered from most significant to least significant in left-to-right order. 
+The large integer does not contain any leading 0's.
+"""
+
+from typing import List
+class Solution:
+    def plusOne(self, digits: List[int]) -> List[int]:
+        n = len(digits)
+        # Start from the rightmost digit
+        for i in range(n - 1, -1, -1):
+            # If the current digit is less than 9, just increment it by 1 and return
+            if digits[i] < 9:
+                digits[i] += 1
+                return digits
+            # Otherwise, set the current digit to 0 and continue with the next digit
+            else:
+                digits[i] = 0
+        # If we reach here, it means all digits were 9, so we need to add a new leading 1
+        digits.insert(0, 1)
+        return digits