View Compilation Error

0_0_33628748_17589.cpp: In function 'int main()':
0_0_33628748_17589.cpp:80:23: error: 'sort' was not declared in this scope
         sort(aa,aa+2*n);
                       ^
0_0_33628748_17589.cpp:81:32: error: 'unique' was not declared in this scope
         int sz=unique(aa,aa+2*n)-aa;
                                ^