View Compilation Error

0_0_17726359_12448.cpp: In function 'int main()':
0_0_17726359_12448.cpp:87:49: error: 'unique' was not declared in this scope
                 dtot = unique(disc+1,disc+1+dtot) - disc - 1;
                                                 ^
0_0_17726359_12448.cpp:87:49: note: suggested alternative:
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/algorithm:62:0,
                 from 0_0_17726359_12448.cpp:3:
GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_algo.h:1022:5: note:   'std::unique'
     unique(_ForwardIterator __first, _ForwardIterator __last,
     ^