refactor 91

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_91.java

@@ -1,49 +1,34 @@
 package com.fishercoder.solutions;
 
-/**
- * 91. Decode Ways
- *
- * A message containing letters from A-Z is being encoded to numbers using the following mapping:
-
- 'A' -> 1
- 'B' -> 2
- ...
- 'Z' -> 26
- Given an encoded message containing digits, determine the total number of ways to decode it.
-
- For example,
- Given encoded message "12", it could be decoded as "AB" (1 2) or "L" (12).
-
- The number of ways decoding "12" is 2.
- */
 public class _91 {
-    /**Credit: https://discuss.leetcode.com/topic/35840/java-clean-dp-solution-with-explanation
+    /**
+     * Credit: https://discuss.leetcode.com/topic/35840/java-clean-dp-solution-with-explanation
      * I used a dp array of size n + 1 to save subproblem solutions.
      * dp[0] means an empty string will have one way to decode,
      * dp[1] means the way to decode a string of size 1.
-     *
      * I then check one digit and two digit combination and save the results along the way.
-     * In the end, dp[n] will be the end result.*/
+     * In the end, dp[n] will be the end result.
+     */
 
     public static class Solution1 {
-      public int numDecodings(String s) {
-        if (s == null || s.length() == 0) {
-          return 0;
-        }
-        int[] dp = new int[s.length() + 1];
-        dp[0] = 1;
-        dp[1] = (s.charAt(0) != '0') ? 1 : 0;
-        for (int i = 2; i <= s.length(); i++) {
-          int first = Integer.valueOf(s.substring(i - 1, i));
-          int second = Integer.valueOf(s.substring(i - 2, i));
-          if (first > 0 && first <= 9) {
-            dp[i] += dp[i - 1];
-          }
-          if (second >= 10 && second <= 26) {
-            dp[i] += dp[i - 2];
-          }
+        public int numDecodings(String s) {
+            if (s == null || s.length() == 0) {
+                return 0;
+            }
+            int[] dp = new int[s.length() + 1];
+            dp[0] = 1;
+            dp[1] = (s.charAt(0) != '0') ? 1 : 0;
+            for (int i = 2; i <= s.length(); i++) {
+                int first = Integer.valueOf(s.substring(i - 1, i));
+                int second = Integer.valueOf(s.substring(i - 2, i));
+                if (first > 0 && first <= 9) {
+                    dp[i] += dp[i - 1];
+                }
+                if (second >= 10 && second <= 26) {
+                    dp[i] += dp[i - 2];
+                }
+            }
+            return dp[s.length()];
         }
-        return dp[s.length()];
-      }
     }
 }