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Author: dingjikerbo

solution/src/main/java/com/inuker/solution/ValidWordAbbr.java

@@ -9,12 +9,12 @@
  */
 
 /**
- * 这道题还挺容易错
  * 参考https://leetcode.com/articles/unique-word-abbreviation/
  */
 public class ValidWordAbbr {
-/** 这题容易错的地方是unique的理解，即dic中不存在该word，要排除word
- *  // 耗时100ms
+    /**
+     * 这题容易错的地方是unique的理解，即dic中不存在该word，要排除word
+     */
     private HashMap<String, Set<String>> mMap;
 
     public ValidWordAbbr(String[] dictionary) {
@@ -31,45 +31,15 @@ public ValidWordAbbr(String[] dictionary) {
         }
     }
 
+    /**
+     * unique意味着不存在该abbr或存在但是只有该单词一个
+     */
     public boolean isUnique(String word) {
         Set<String> set = mMap.get(getAbbr(word));
         return set == null || (set.size() == 1 && set.contains(word));
     }
 
-    private String getAbbr(String word) {
-        int len = word.length();
-        if (len == 0) {
-            return "";
-        }
-        return word.charAt(0) + String.valueOf(len - 2) + word.charAt(len - 1);
-    }*/
-
-    private HashMap<String, Integer> mMap;
-    private Set<String> mSet;
-
-    // 耗时69ms，比上面的快一点
-    public ValidWordAbbr(String[] dictionary) {
-        mMap = new HashMap<String, Integer>();
-        mSet = new HashSet<String>();
-        for (String text : dictionary) {
-            String abbr = getAbbr(text);
-
-            if (mSet.add(text)) {
-                mMap.put(abbr, mMap.containsKey(abbr) ? mMap.get(abbr) + 1 : 1);
-            }
-        }
-    }
-
-    public boolean isUnique(String word) {
-        String abbr = getAbbr(word);
-        return !mMap.containsKey(abbr) || (mMap.get(abbr) == 1 && mSet.contains(word));
-    }
-
-    private String getAbbr(String word) {
-        int len = word.length();
-        if (len == 0) {
-            return "";
-        }
-        return word.charAt(0) + String.valueOf(len - 2) + word.charAt(len - 1);
+    private String getAbbr(String s) {
+        return s.length() > 2 ? s.substring(0, 1) + (s.length() - 2) + s.substring(s.length() - 1) : s;
     }
 }

test/src/main/java/com/inuker/test/main.java

@@ -11,43 +11,49 @@
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.Deque;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Set;
 import java.util.Stack;
 
 public class main {
 
     public static void main(String[] args) {
-        String s = decodeString("2[abc]3[cd]ef");
+        Codec c = new Codec();
+        String s = c.encode(Arrays.asList("hello", "how", "are", "you"));
         System.out.println(s);
+        for (String ss : c.decode(s)) {
+            System.out.println(ss);
+        }
     }
 
-    public static String decodeString(String s) {
-        StringBuilder stack = new StringBuilder();
-        for (char c : s.toCharArray()) {
-            if (c != ']') {
-                stack.append(c);
-            } else {
-                StringBuilder sb = new StringBuilder();
-                while (stack.charAt(stack.length() - 1) != '[') {
-                    sb.insert(0, stack.charAt(stack.length() - 1));
-                    stack.setLength(stack.length() - 1);
-                }
-                stack.setLength(stack.length() - 1);
-                int n = 0, t = 1;
-                while (stack.length() > 0 && Character.isDigit(stack.charAt(stack.length() - 1))) {
-                    n += t * (stack.charAt(stack.length() - 1) - '0');
-                    t *= 10;
-                    stack.setLength(stack.length() - 1);
-                }
-                for (int i = 0; i < n; i++) {
-                    for (int j = 0; j < sb.length(); j++) {
-                        stack.append(sb.charAt(j));
-                    }
-                }
+    class ValidWordAbbr {
+
+        HashMap<String, Set<String>> map = new HashMap<>();
+
+        public ValidWordAbbr(String[] dictionary) {
+            for (String s : dictionary) {
+                String abbr = getAbbr(s);
+                Set<String> set = map.getOrDefault(abbr, new HashSet<String>());
+                set.add(s);
+                map.put(abbr, set);
+            }
+        }
+
+        private String getAbbr(String s) {
+            return s.length() > 2 ? s.substring(0, 1) + (s.length() - 2) + s.substring(s.length() - 1) : s;
+        }
+
+        public boolean isUnique(String word) {
+            String abbr = getAbbr(word);
+            if (!map.containsKey(abbr)) {
+                return true;
             }
+            Set<String> set = map.get(abbr);
+            return set.size() == 1 && set.contains(word);
         }
-        return stack.toString();
     }
 }