Language: C++

#include<bits/stdc++.h>
using namespace std; 
 
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize ("-ffloat-store")  
#pragma GCC optimize ("-fno-defer-pop")
 
typedef long long int ll; 
typedef long double ld; 
 
#define MAX 300005
#define endl endl
#define UPPER 1000000000

ll H, W;
ll C1, C2, D1, D2;
vector<string> vec;
vector<vector<ll>> flg(1000+1, vector<ll>(1000+1, 0));
vector<vector<ll>> cost(1000+1, vector<ll>(1000+1, 1e18));
set < pair<ll, pair<ll,ll> > > q;
	
int main(){
	
	std::ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);

	ll H, W;
	cin>>H>>W;
	
	vector<ll> vec[H+1];
	ll m;
	cin>>m;
	unordered_map<ll,ll> col;
	map<ll,ll> mp;
	for(ll i=0;i<m;++i){
		ll a, b;
		cin>>a>>b;
		vec[a].push_back(b);
		
		col[b]++;
	}	
	
	for(auto it: col){
		mp[it.second]++;
	}
	
	ll ans = 0;
	for(ll i=1;i<=H;i++){
		for(ll j: vec[i]){
			mp[col[j]]--;
			if(mp[col[j]]==0){
				mp.erase(col[j]);
			}
			col[j]--;
			mp[col[j]]++;
		}
		if(mp.size()!=0)
			ans = max(ans, vec[i].size()+(*(--mp.end())).first);
		for(ll j: vec[i]){
			mp[col[j]]--;
			if(mp[col[j]]==0){
				mp.erase(col[j]);
			}
			col[j]++;
			mp[col[j]]++;
		}
	}
	
	cout<<ans<<endl;
	
	
	
}


Compiler output:
a.cc: In function 'int main()':
a.cc:60:34: error: no matching function for call to 'max(ll&, long long unsigned int)'
   60 |                         ans = max(ans, vec[i].size()+(*(--mp.end())).first);
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:60:34: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'long long unsigned int')
   60 |                         ans = max(ans, vec[i].size()+(*(--mp.end())).first);
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:60:34: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   60 |                         ans = max(ans, vec[i].size()+(*(--mp.end())).first);
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~