My solution-
int ans=0;
void dfs(int n,vector<vector<int>>&adj,vector<int>&vis,unordered_map<pair<int,int> , int>&mp){
vis[n]=1;
for(int i=0;i<adj[n].size();i++){
if(vis[adj[n][i]]==0){
if(mp.find({adj[n][i],n})==mp.end()){ans++;}
dfs(adj[n][i],adj,vis,mp);
}
}
}
int minReorder(int n, vector<vector<int>>& connections) {
vector<vector<int>>adj(n);
unordered_map< pair<int,int> , int>mp;
for(int i=0;i<connections.size();i++){
adj[connections[i][0]].push_back(connections[i][1]);
adj[connections[i][1]].push_back(connections[i][0]);
mp[{connections[i][0],connections[i][1]}]=1;
}
vector<int>vis(n,0);
for(int i=0;i<n;i++){
if(vis[i]==0){
dfs(i,adj,vis,mp);
}
}
return ans;
}
Getting this error.
Line 17: Char 44: error: call to implicitly-deleted default constructor of 'unordered_map<pair<int, int>, int>' unordered_map< pair<int,int> , int>mp; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/unordered_map.h:141:7: note: explicitly defaulted function was implicitly deleted here unordered_map() = default; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/unordered_map.h:105:18: note: default constructor of 'unordered_map<std::pair<int, int>, int, std::hash<std::pair<int, int>>, std::equal_to<std::pair<int, int>>, std::allocator<std::pair<const std::pair<int, int>, int>>>' is implicitly deleted because field '_M_h' has a deleted default constructor _Hashtable _M_h; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/hashtable.h:414:7: note: explicitly defaulted function was implicitly deleted here _Hashtable() = default; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/hashtable.h:174:7: note: default constructor of '_Hashtable<std::pair<int, int>, std::pair<const std::pair<int, int>, int>, std::allocator<std::pair<const std::pair<int, int>, int>>, std::__detail::_Select1st, std::equal_to<std::pair<int, int>>, std::hash<std::pair<int, int>>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, std::__detail::_Hashtable_traits<true, false, true>>' is implicitly deleted because base class '__detail::_Hashtable_base<pair<int, int>, pair<const pair<int, int>, int>, _Select1st, equal_to<pair<int, int>>, hash<pair<int, int>>, _Mod_range_hashing, _Default_ranged_hash, _Hashtable_traits<true, false, true>>' has a deleted default constructor : public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/hashtable_policy.h:1822:5: note: explicitly defaulted function was implicitly deleted here _Hashtable_base() = default; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/hashtable_policy.h:1771:5: note: default constructor of '_Hashtable_base<std::pair<int, int>, std::pair<const std::pair<int, int>, int>, std::__detail::_Select1st, std::equal_to<std::pair<int, int>>, std::hash<std::pair<int, int>>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Hashtable_traits<true, false, true>>' is implicitly deleted because base class '_Hash_code_base<std::pair<int, int>, std::pair<const std::pair<int, int>, int>, std::__detail::_Select1st, std::hash<std::pair<int, int>>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, _Hashtable_traits<true, false, true>::__hash_cached::value>' has a deleted default constructor : public _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/hashtable_policy.h:1373:7: note: explicitly defaulted function was implicitly deleted here _Hash_code_base() = default; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/hashtable_policy.h:1349:7: note: default constructor of '_Hash_code_base<std::pair<int, int>, std::pair<const std::pair<int, int>, int>, std::__detail::_Select1st, std::hash<std::pair<int, int>>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, true>' is implicitly deleted because base class '_Hashtable_ebo_helper<1, std::hash<std::pair<int, int>>>' has a deleted default constructor private _Hashtable_ebo_helper<1, _H1>, ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/hashtable_policy.h:1096:7: note: explicitly defaulted function was implicitly deleted here _Hashtable_ebo_helper() = default; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/hashtable_policy.h:1094:7: note: default constructor of '_Hashtable_ebo_helper<1, std::hash<std::pair<int, int>>, true>' is implicitly deleted because base class 'std::hash<std::pair<int, int>>' has a deleted default constructor : private _Tp ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/functional_hash.h:101:19: note: default constructor of 'hash<std::pair<int, int>>' is implicitly deleted because base class '__hash_enum<std::pair<int, int>>' has no default constructor struct hash : __hash_enum<_Tp>
Pls help
^
