decode-ways solution

Author: sejineer

decode-ways/sejineer.py

@@ -0,0 +1,17 @@
+"""
+시간 복잡도: O(N)
+공간 복잡도: O(N)
+"""
+class Solution:
+    def numDecodings(self, s: str) -> int:
+        dp = [0] * len(s) + [1]
+
+        for i in reversed(range(len(s))):
+            if s[i] == "0":
+                dp[i] = 0
+            elif i + 1 < len(s) and int(s[i : i + 2]) < 27:
+                dp[i] = dp[i + 1] + dp[i + 2]
+            else:
+                dp[i] = dp[i + 1]
+        
+        return dp[0]