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Author: assassint2017

Decode Ways/Decode_Ways.py

@@ -0,0 +1,14 @@
+# 动态规划
+# 40ms 100%
+class Solution:
+    def numDecodings(self, s):
+        if not s:
+            return 0
+        dp = [0 for _ in range(len(s)+1)]
+        dp[0] = 1
+        for i in range(1, len(s)+1):
+            if s[i-1] != "0":
+                dp[i] += dp[i-1]
+            if i != 1 and '10' <= s[i-2:i] <= "26":
+                dp[i] += dp[i-2]
+        return dp[-1]