unordered map key is pair code example
Example: unordered_map of pair and int
struct HASH{
size_t operator()(const pair<int,int>&x)const{
return hash<long long>()(((long long)x.first)^(((long long)x.second)<<32));
}
};
unordered_map<pair<int,int>,int,HASH>mp;
//In Function pass it as
int foo(unordered_map<pair<int,int>,int,HASH> &mp);