Decode Ways Solution

decode-ways/kayden.py

@@ -0,0 +1,21 @@
+# 시간복잡도: O(N)
+# 공간복잡도: O(N)
+class Solution:
+    def numDecodings(self, s: str) -> int:
+        if s[0] == "0":
+            return 0
+
+        n = len(s)
+        dp = [0] * (n + 1)
+        dp[0] = 1
+        dp[1] = 1
+
+        for i in range(2, n + 1):
+
+            if int(s[i - 1]) != 0:
+                dp[i] += dp[i - 1]
+
+            if 10 <= int(s[i - 2:i]) <= 26:
+                dp[i] += dp[i - 2]
+
+        return dp[n]