Merge pull request #563 from openset/develop

Update: description

Author: Shuo

problems/last-stone-weight/README.md

@@ -22,9 +22,34 @@
 
 <p>At the end, there is at most 1 stone left.&nbsp; Return the weight of this stone (or 0 if there are no stones left.)</p>
 
+<p>&nbsp;</p>
+
+<p><strong>Example 1:</strong></p>
+
+<pre>
+<strong>Input: </strong>[2,7,4,1,8,1]
+<strong>Output: </strong>1
+<strong>Explanation: </strong>
+We combine 7 and 8 to get 1 so the array converts to [2,4,1,1,1] then,
+we combine 2 and 4 to get 2 so the array converts to [2,1,1,1] then,
+we combine 2 and 1 to get 1 so the array converts to [1,1,1] then,
+we combine 1 and 1 to get 0 so the array converts to [1] then that&#39;s the value of last stone.</pre>
+
+<p>&nbsp;</p>
+
 <p><strong>Note:</strong></p>
 
 <ol>
 	<li><code>1 &lt;= stones.length &lt;= 30</code></li>
 	<li><code>1 &lt;= stones[i] &lt;= 1000</code></li>
 </ol>
+
+### Related Topics
+  [[Heap](https://github.com/openset/leetcode/tree/master/tag/heap/README.md)]
+  [[Greedy](https://github.com/openset/leetcode/tree/master/tag/greedy/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Simulate the process.  We can do it with a heap, or by sorting some list of stones every time we take a turn.
+</details>

problems/longest-string-chain/README.md

@@ -42,3 +42,17 @@
 <div>
 <p>&nbsp;</p>
 </div>
+
+### Related Topics
+  [[Hash Table](https://github.com/openset/leetcode/tree/master/tag/hash-table/README.md)]
+  [[Dynamic Programming](https://github.com/openset/leetcode/tree/master/tag/dynamic-programming/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Instead of adding a character, try deleting a character to form a chain in reverse.
+</details>
+<details>
+<summary>Hint 2</summary>
+For each word in order of length, for each word2 which is word with one character removed, length[word2] = max(length[word2], length[word] + 1).
+</details>

problems/remove-all-adjacent-duplicates-in-string/README.md

@@ -36,3 +36,12 @@ For example, in "abbaca" we could remove "bb" since the lett
 	<li><code>1 &lt;= S.length &lt;= 20000</code></li>
 	<li><code>S</code> consists only of English lowercase letters.</li>
 </ol>
+
+### Related Topics
+  [[Stack](https://github.com/openset/leetcode/tree/master/tag/stack/README.md)]
+
+### Hints
+<details>
+<summary>Hint 1</summary>
+Use a stack to process everything greedily.
+</details>