View Compilation Error

0_0_33879105_1847.cpp: In function 'void compute(Node*, int)':
0_0_33879105_1847.cpp:22:16: error: 'sort' was not declared in this scope
  sort(x,x+m,cmp);
                ^
0_0_33879105_1847.cpp:22:16: note: suggested alternative:
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/algorithm:62:0,
                 from 0_0_33879105_1847.cpp:4:
GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_algo.h:4705:5: note:   'std::sort'
     sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
     ^