View Compilation Error

0_0_25842769_5945.cpp:18:1: error: 'unordered_map' does not name a type
 unordered_map<ipp, int> mp;
 ^
0_0_25842769_5945.cpp: In function 'void init()':
0_0_25842769_5945.cpp:27:5: error: 'mp' was not declared in this scope
     mp.clear();
     ^
0_0_25842769_5945.cpp: In function 'void addEdg(int, int, ll)':
0_0_25842769_5945.cpp:41:28: error: 'mp' was not declared in this scope
     ipp t=make_pair(u, v); mp[t]=cnt;
                            ^
0_0_25842769_5945.cpp: In function 'void cal_cir(int, int)':
0_0_25842769_5945.cpp:51:24: error: 'mp' was not declared in this scope
         tmp[++num]=edg[mp[t]];
                        ^
0_0_25842769_5945.cpp:55:20: error: 'mp' was not declared in this scope
     tmp[++num]=edg[mp[t]];
                    ^