[Function add]

1. Add leetcode solution.

Author: Seanforfun

Diff for: leetcode/292. Nim Game.md

@@ -0,0 +1,27 @@
+## 292. Nim Game
+
+### Question
+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.
+
+```
+Example:
+
+Input: 4
+Output: false
+Explanation: 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.
+```
+
+### Thinking:
+* Method 1:
+	* 4的倍数无法获胜。
+
+```Java
+class Solution {
+    public boolean canWinNim(int n) {
+        return n % 4 != 0;
+    }
+}
+```

Diff for: leetcode/295.Find Median from Data Stream.md

@@ -0,0 +1,60 @@
+## 295.Find Median from Data Stream
+
+### Question
+Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two middle value.
+For example,
+
+[2,3,4], the median is 3
+
+[2,3], the median is (2 + 3) / 2 = 2.5
+
+Design a data structure that supports the following two operations:
+
+* void addNum(int num) - Add a integer number from the data stream to the data structure.
+* double findMedian() - Return the median of all elements so far.
+
+```
+Example:
+
+addNum(1)
+addNum(2)
+findMedian() -> 1.5
+addNum(3)
+findMedian() -> 2
+```
+
+### Thinking:
+* Method 1:
+	* 通过堆结构来实现，堆结构是通过优先级队列实现的。
+	* 维护一个递增堆和一个递减堆。
+	* 通过判断两个堆的size判断总数是奇数还是偶数。
+
+```Java
+class MedianFinder {
+    private List<Integer> list;
+    /** initialize your data structure here. */
+    public MedianFinder() {
+        this.list = new ArrayList<>();
+    }
+
+    public void addNum(int num) {
+        list.add(num);
+    }
+
+    public double findMedian() {
+        int size = list.size();
+        if(size % 2 != 0)
+            return (double)list.get(size / 2);
+        else{
+            return (double)(list.get(size / 2) + list.get(size / 2 - 1)) / 2;
+        }
+    }
+}
+
+/**
+ * Your MedianFinder object will be instantiated and called as such:
+ * MedianFinder obj = new MedianFinder();
+ * obj.addNum(num);
+ * double param_2 = obj.findMedian();
+ */
+```