View Compilation Error

0_0_21334481_3061.cpp: In function 'int main()':
0_0_21334481_3061.cpp:38:19: error: 'sort' was not declared in this scope
   sort(id,id+m,cmp);
                   ^
0_0_21334481_3061.cpp:45:31: error: 'nth_element' was not declared in this scope
     nth_element(s,s+now,s+last);
                               ^