View Compilation Error

0_0_31111829_20834.cpp: In function 'int main()':
0_0_31111829_20834.cpp:24:25: error: 'sort' was not declared in this scope
   sort(ord+1,ord+n+1,cmp);s.clear();
                         ^
0_0_31111829_20834.cpp:31:26: error: 'abs' was not declared in this scope
    ans=min(ans,abs(x[t]-k));
                          ^