add 527

Author: fishercoder1534

README.md

@@ -100,6 +100,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |531|[Lonely Pixel I](https://leetcode.com/problems/lonely-pixel-i/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_531.java) | O(m*n) |O(1) | Medium | 
 |530|[Minimum Absolute Difference in BST](https://leetcode.com/problems/minimum-absolute-difference-in-bst/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_530.java) | O(n) |O(n) | Easy| DFS
 |529|[Minesweeper](https://leetcode.com/problems/minesweeper/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_529.java) | O(m*n) |O(k) | Medium | BFS
+|527|[Word Abbreviation](https://leetcode.com/problems/word-abbreviation/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_527.java) | O(n^2) |O(n) | Hard | 
 |526|[Beautiful Arrangement](https://leetcode.com/problems/beautiful-arrangement/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_526.java) | O(n) |O(h) | Medium | Backtracking
 |525|[Contiguous Array](https://leetcode.com/problems/contiguous-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_525.java) | O(n) |O(n) | Medium | HashMap
 |524|[Longest Word in Dictionary through Deleting](https://leetcode.com/problems/longest-word-in-dictionary-through-deleting/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_524.java) | O(n) |O(n) | Medium | Sort

src/main/java/com/fishercoder/solutions/_527.java

@@ -0,0 +1,70 @@
+package com.fishercoder.solutions;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+
+/**
+ * 527. Word Abbreviation
+ *
+ * Given an array of n distinct non-empty strings, you need to generate minimal possible abbreviations for every word following rules below.
+
+ Begin with the first character and then the number of characters abbreviated, which followed by the last character.
+ If there are any conflict, that is more than one words share the same abbreviation,
+ a longer prefix is used instead of only the first character until making the map
+ from word to abbreviation become unique.
+ In other words, a final abbreviation cannot map to more than one original words.
+ If the abbreviation doesn't make the word shorter, then keep it as original.
+
+ Example:
+ Input: ["like", "god", "internal", "me", "internet", "interval", "intension", "face", "intrusion"]
+ Output: ["l2e","god","internal","me","i6t","interval","inte4n","f2e","intr4n"]
+
+ Note:
+ Both n and the length of each word will not exceed 400.
+ The length of each word is greater than 1.
+ The words consist of lowercase English letters only.
+ The return answers should be in the same order as the original array.
+ */
+public class _527 {
+
+    /**reference: https://discuss.leetcode.com/topic/82613/really-simple-and-straightforward-java-solution*/
+    public List<String> wordsAbbreviation(List<String> dict) {
+        int len = dict.size();
+        String[] ans = new String[len];
+        int[] prefix = new int[len];
+        for (int i = 0; i < len; i++) {
+            prefix[i] = 1;
+            ans[i] = abbreviate(dict.get(i), 1); // make abbreviation for each string
+        }
+        for (int i = 0; i < len; i++) {
+            while (true) {
+                HashSet<Integer> set = new HashSet<>();
+                for (int j = i + 1; j < len; j++) {
+                    if (ans[j].equals(ans[i])) set.add(j); // check all strings with the same abbreviation
+                }
+                if (set.isEmpty()) break;
+                set.add(i);
+                for (int k : set)
+                    ans[k] = abbreviate(dict.get(k), ++prefix[k]); // increase the prefix
+            }
+        }
+        return Arrays.asList(ans);
+    }
+
+    private String abbreviate(String word, int k) {
+        if (k + 2 >= word.length()) {
+            return word;
+        }
+        StringBuilder stringBuilder = new StringBuilder();
+        stringBuilder.append(word.substring(0, k));
+        stringBuilder.append(word.length() - 1 - k);
+        stringBuilder.append(word.substring(word.length()-1));
+        return stringBuilder.toString();
+    }
+
+    public static void main(String... args) {
+        _527 test = new _527();
+        System.out.println(test.abbreviate("saaap", 2));
+    }
+}