paper works for "Nim Game"

Author: haoel

README.md

@@ -8,6 +8,7 @@ LeetCode
 
 | # | Title | Solution | Difficulty |
 |---| ----- | -------- | ---------- |
+|292|[Nim Game](https://leetcode.com/problems/nim-game/)  | [C++](./algorithms/cpp/nimGame/nimGame.cpp)|Easy|
 |285|[Inorder Successor in BST](https://leetcode.com/problems/inorder-successor-in-bst/) ♥ | [Java](./algorithms/java/src/inorderSuccessorInBST/inorderSuccessorInBST.java)|Medium|
 |278|[First Bad Version](https://leetcode.com/problems/first-bad-version/)| [C++](./algorithms/cpp/firstBadVersion/FirstBadVersion.cpp), [Java](./algorithms/java/src/firstBadVersion/firstBadVersion.java)|Easy|
 |258|[Add Digits](https://leetcode.com/problems/add-digits/)| [C++](./algorithms/cpp/addDigits/addDigits.cpp)|Easy|

algorithms/cpp/nimGame/nimGame.cpp

@@ -2,43 +2,68 @@
 // Author : Calinescu Valentin
 // Date   : 2015-10-19
 
-/********************************************************************************** 
- * You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3
- * stones. The one who removes the last stone will be the winner. You will take the first turn to remove the stones.
+/*************************************************************************************** 
  *
- * Both of you are very clever and have optimal strategies for the game. Write a function to determine whether you can win the game given the number of
- * stones in the heap.
- *
- * For example, if there are 4 stones in the heap, then you will never win the game: no matter 1, 2, or 3 stones you remove, the last stone will always be
- * removed by your friend.
+ * You are playing the following Nim Game with your friend: There is a heap of stones 
+ * on the table, each time one of you take turns to remove 1 to 3 stones. The one who 
+ * removes the last stone will be the winner. You will take the first turn to remove 
+ * the stones.
+ * 
+ * Both of you are very clever and have optimal strategies for the game. Write a 
+ * function to determine whether you can win the game given the number of stones in the 
+ * heap.
+ * 
+ * For example, if there are 4 stones in the heap, then you will never win the game: no 
+ * matter 1, 2, or 3 stones you remove, the last stone will always be removed by your 
+ * friend.
+ * 
+ *   If there are 5 stones in the heap, could you figure out a way to remove the stones 
+ * such that you will always be the winner? 
+ * 
+ * Credits:Special thanks to @jianchao.li.fighter for adding this problem and creating 
+ * all test cases.
+ *               
+ ***************************************************************************************/
+
+
+
+/* 
+ * Solutions
+ * =========
  *
- **********************************************************************************/
-/********************************************************************************** 
  * Let's look at the example:
  * 
- * 0 stones - false
- * 1 stone - true
- * 2 stones - true
- * 3 stones - true
- * 4 stones - false
+ *    0 stones - false
+ *    1 stone - true
+ *    2 stones - true
+ *    3 stones - true
+ *    4 stones - false
  * 
- * We notice that all we need for a position to be true is to get the opponent in a position that is false. With 1, 2 and 3 you can take 1, 2 and 3
- * stones respectively to force your opponent into having 0 stones, a position where he cannot win. No matter how many stones we take from 4 we cannot 
- * force the opponent into a losing positon, so position 4 becomes a losing position. Let's take a look at the next 4 positions:
+ * We notice that all we need for a position to be true is to get the opponent in a position 
+ * that is false. With 1, 2 and 3 you can take 1, 2 and 3 stones respectively to force your 
+ * opponent into having 0 stones, a position where he cannot win. No matter how many stones 
+ * we take from 4 we cannot 
+ *
+ * force the opponent into a losing positon, so position 4 becomes a losing position. 
+ * Let's take a look at the next 4 positions:
  * 
- * 5 stones - true
- * 6 stones - true
- * 7 stones - true
- * 8 stones - false
+ *     5 stones - true
+ *     6 stones - true
+ *     7 stones - true
+ *     8 stones - false
  * 
- * With 5, 6 and 7 stones we can take 1, 2 and 3 stones respectively to force the opponent into position 4. Position 8 is a losing one because we can 
- * only force the opponent into winning positions. We notice that this group of 4 positions can repeat itself indefinitely, because we only need the
- * previous 3 positions to judge whether a position is winning or losing. Thus we can see the pattern:
+ * With 5, 6 and 7 stones we can take 1, 2 and 3 stones respectively to force the opponent into 
+ * position 4. Position 8 is a losing one because we can only force the opponent into winning 
+ * positions. We notice that this group of 4 positions can repeat itself indefinitely, because 
+ * we only need the previous 3 positions to judge whether a position is winning or losing. 
+ *
+ * Thus we can see the pattern:
  * 
- * n % 4 == 0 - false
- * n % 4 != 0 - true
+ *     n % 4 == 0 - false
+ *     n % 4 != 0 - true
  * 
- **********************************************************************************/
+ */
+
 class Solution {
 public:
     bool canWinNim(int n) {