decode-ways solution

Author: yayyz

decode-ways/yayyz.py

@@ -0,0 +1,13 @@
+class Solution:
+    def numDecodings(self, s: str) -> int:
+        n = len(s)
+        dp = [0] * (n + 1)
+        dp[n] = 1  # 빈 문자열 처리
+
+        for i in range(n - 1, -1, -1):
+            if s[i] != "0":
+                dp[i] += dp[i + 1]
+                if i + 1 < n and int(s[i:i+2]) <= 26:
+                    dp[i] += dp[i + 2]
+
+        return dp[0]