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diff --git a/meowpp/dsa/BinaryIndexTree.h b/meowpp/dsa/BinaryIndexTree.h
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+#ifndef   __BinaryIndexTree_H__
+#define   __BinaryIndexTree_H__
+
+namespace meow{
+  //#
+  //#=== meow:: *BinaryIndexTree<Value>* (C++ class)
+  //#==== Description
+  //#  極度簡化版的 `SegmentTree` 已無法區間操作, 區間詢問的區間開頭也一定要
+  //#  在 `index=0` 的地方
+  //#
+  //#==== Template Class Operators Request
+  //#[options="header",width="70%",cols="1>m,1<,3<s,5<,3<,15<",grid="rows"]
+  //#|=====================================================================
+  //#|Const?|Typename| Operator  | Parameters  | Return_Type| Description
+  //#|const |  Value | operator+ |(Value  `n`) | Value      | 合併用(類似
+  //#                                                         `SegmentTree` 的
+  //#                                                         operator{b} )
+  //#|=====================================================================
+  //#
+  template<class Value>
+  class BinaryIndexTree{
+    private:
+      std::vector<Value> _array;
+    public:
+      BinaryIndexTree();
+      BinaryIndexTree(size_t __size, Value const& __value);
+      BinaryIndexTree(BinaryIndexTree const& __tree2);
+      
+      //#==== Support Methods
+      //#
+      //# * N <- `this` 中擁有的資料數
+      //#
+      //#[options="header",width="100%",cols="1>m,3>s,7<,3<,3^,20<",grid="rows"]
+      //#|=====================================================================
+      //#|Const?|Name | Parameters   | Return_Type| Time_Complexity| Description
+      
+      
+      //#||reset|(size_t `size`, Value const& `value`)|void|O(`size`)
+      //#|將資料長度刷成 `N = size` 且每一個元素都是 `value`
+      void reset(size_t __size, Value const& __value);
+      
+      
+      //#||update|(size_t `index`, Value const& `value`)|void|O(logN)
+      //#|將第 `index` (從零開始算) 多加上 `value`
+      void  update( size_t __index, Value const& __value);
+      
+      
+      //#|const|query|(size_t `index`)|void|O(logN)
+      //#|詢問 `0~index` 的區間值
+      Value query (ssize_t __index) const;
+      
+      
+      //#|=====================================================================
+  };
+  //#
+  //#[NOTE]
+  //#========================================
+  //# * 一般來說只能用在維護區間總和, 維護區間最大值只有在特殊情況才可以, 即
+  //#   '針對每個元素, 每次 update() 的值一定會大於等於原本的值' 
+  //# * 若要用區間最大值 , 則 `Value` 的 `operator+` 要寫成 `std::max(...)`
+  //#========================================
+  //#
+  //# '''
+}
+
+#include "BinaryIndexTree.hpp"
+
+#endif // BinaryIndexTree_H__
+