refactor 639

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_639.java

@@ -31,34 +31,38 @@
 
  */
 public class _639 {
-    /**reference: https://leetcode.com/articles/decode-ways-ii/#approach-2-dynamic-programming-accepted*/
-    int m = 1000000007;
+    public static class Solution1 {
+        /**
+         * reference: https://leetcode.com/articles/decode-ways-ii/#approach-2-dynamic-programming-accepted
+         */
+        int m = 1000000007;
 
-    public int numDecodings(String s) {
-        long[] dp = new long[s.length() + 1];
-        dp[0] = 1;
-        dp[1] = s.charAt(0) == '*' ? 9 : s.charAt(0) == '0' ? 0 : 1;
-        for (int i = 1; i < s.length(); i++) {
-            if (s.charAt(i) == '*') {
-                dp[i + 1] = 9 * dp[i];
-                if (s.charAt(i - 1) == '1') {
-                    dp[i + 1] = (dp[i + 1] + 9 * dp[i - 1]) % m;
-                } else if (s.charAt(i - 1) == '2') {
-                    dp[i + 1] = (dp[i + 1] + 6 * dp[i - 1]) % m;
-                } else if (s.charAt(i - 1) == '*') {
-                    dp[i + 1] = (dp[i + 1] + 15 * dp[i - 1]) % m;
-                }
-            } else {
-                dp[i + 1] = s.charAt(i) != '0' ? dp[i] : 0;
-                if (s.charAt(i - 1) == '1') {
-                    dp[i + 1] = (dp[i + 1] + dp[i - 1]) % m;
-                } else if (s.charAt(i - 1) == '2' && s.charAt(i) <= '6') {
-                    dp[i + 1] = (dp[i + 1] + dp[i - 1]) % m;
-                } else if (s.charAt(i - 1) == '*') {
-                    dp[i + 1] = (dp[i + 1] + (s.charAt(i) <= '6' ? 2 : 1) * dp[i - 1]) % m;
+        public int numDecodings(String s) {
+            long[] dp = new long[s.length() + 1];
+            dp[0] = 1;
+            dp[1] = s.charAt(0) == '*' ? 9 : s.charAt(0) == '0' ? 0 : 1;
+            for (int i = 1; i < s.length(); i++) {
+                if (s.charAt(i) == '*') {
+                    dp[i + 1] = 9 * dp[i];
+                    if (s.charAt(i - 1) == '1') {
+                        dp[i + 1] = (dp[i + 1] + 9 * dp[i - 1]) % m;
+                    } else if (s.charAt(i - 1) == '2') {
+                        dp[i + 1] = (dp[i + 1] + 6 * dp[i - 1]) % m;
+                    } else if (s.charAt(i - 1) == '*') {
+                        dp[i + 1] = (dp[i + 1] + 15 * dp[i - 1]) % m;
+                    }
+                } else {
+                    dp[i + 1] = s.charAt(i) != '0' ? dp[i] : 0;
+                    if (s.charAt(i - 1) == '1') {
+                        dp[i + 1] = (dp[i + 1] + dp[i - 1]) % m;
+                    } else if (s.charAt(i - 1) == '2' && s.charAt(i) <= '6') {
+                        dp[i + 1] = (dp[i + 1] + dp[i - 1]) % m;
+                    } else if (s.charAt(i - 1) == '*') {
+                        dp[i + 1] = (dp[i + 1] + (s.charAt(i) <= '6' ? 2 : 1) * dp[i - 1]) % m;
+                    }
                 }
             }
+            return (int) dp[s.length()];
         }
-        return (int) dp[s.length()];
     }
 }