View Compilation Error

0_0_29292731_3901.cpp: In function 'int main()':
0_0_29292731_3901.cpp:83:18: error: 'sort' was not declared in this scope
  sort(b+1,b+len+1);
                  ^
0_0_29292731_3901.cpp:84:24: error: 'unique' was not declared in this scope
  len=unique(b+1,b+len+1)-b-1;
                        ^
0_0_29292731_3901.cpp:87:36: error: 'upper_bound' was not declared in this scope
   x[i]=upper_bound(b+1,b+len+1,x[i])-b-1;
                                    ^