View Compilation Error

0_0_37382768_29969.cpp: In function 'int main()':
0_0_37382768_29969.cpp:9:2: error: 'map' was not declared in this scope
  map<int, int>m;
  ^
0_0_37382768_29969.cpp:9:6: error: expected primary-expression before 'int'
  map<int, int>m;
      ^
0_0_37382768_29969.cpp:22:23: error: 'm' was not declared in this scope
    if (p[ans] == 0) { m[ans] = a; p[ans] = ans; }
                       ^
0_0_37382768_29969.cpp:24:11: error: 'm' was not declared in this scope
   cout << m[*max_element(p, p + 20010)] << endl;
           ^