实验了一个 rope 套 pbds 的平衡树，代码如下：

rope<tree<pair<int, int>, null_type, less<pair<int, int> >, rb_tree_tag, tree_order_statistics_node_update> >a;

但是报了错误，似乎是有些符号没定义，应该怎么改捏？

[
In file included from C:/Users/Lenovo_/AppData/Local/Temp/CP Editor-vqicEw/sol.cpp:2:0: 
D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/ext/rope: In instantiation of 'void __gnu_cxx::_Rope_RopeSubstring<_CharT, _Alloc>::operator()(std::size_t, std::size_t, _CharT*) [with _CharT = __gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type, std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>; _Alloc = std::allocator<__gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type, std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update> >; std::size_t = long long unsigned int]': 
C:/Users/Lenovo_/AppData/Local/Temp/CP Editor-vqicEw/sol.cpp:18:1:   required from here 
D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/ext/rope:879:16: error: call of overloaded 'uninitialized_copy_n(__gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type, std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>*, std::size_t&, __gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type, std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>*&)' is ambiguous 
        __buffer); 
                ^ 
D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/ext/rope:879:16: note: candidates are: 
In file included from D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/ext/rope:64:0, 
                 from C:/Users/Lenovo_/AppData/Local/Temp/CP Editor-vqicEw/sol.cpp:2: 
D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/ext/memory:122:5: note: std::pair<_InputIter, _ForwardIter> __gnu_cxx::uninitialized_copy_n(_InputIter, _Size, _ForwardIter) [with _InputIter = __gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type, std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>*; _Size = long long unsigned int; _ForwardIter = __gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type, std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>*] 
     uninitialized_copy_n(_InputIter __first, _Size __count, 
     ^ 
In file included from D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/vector:63:0, 
                 from D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/bits/random.h:34, 
                 from D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/random:49, 
                 from D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/bits/stl_algo.h:66, 
                 from D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/algorithm:62, 
                 from D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/x86_64-w64-mingw32/bits/stdc++.h:64, 
                 from C:/Users/Lenovo_/AppData/Local/Temp/CP Editor-vqicEw/sol.cpp:1: 
D:/ProgramFiles/Dev-Cpp/MinGW64/lib/gcc/x86_64-w64-mingw32/4.9.2/include/c++/bits/stl_uninitialized.h:673:5: note: _ForwardIterator std::uninitialized_copy_n(_InputIterator, _Size, _ForwardIterator) [with _InputIterator = __gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type, std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>*; _Size = long long unsigned int; _ForwardIterator = __gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type, std::less<std::pair<int, int> >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>*] 
     uninitialized_copy_n(_InputIterator __first, _Size __n, 
     ^ 
]