View Compilation Error

0_0_25851499_15024.cpp:21:1: error: 'hash_map' does not name a type
 hash_map<pc,int>M;
 ^
0_0_25851499_15024.cpp: In function 'void dij()':
0_0_25851499_15024.cpp:71:8: error: 'M' was not declared in this scope
    if(!M[tt]) {
        ^
0_0_25851499_15024.cpp: In function 'int main()':
0_0_25851499_15024.cpp:88:3: error: 'M' was not declared in this scope
   M.clear();
   ^