Language: C++

#include<bits/stdc++.h>
typedef long long ll;
using namespace std;

struct tr{
    ll x,y;
};

bool operator < (tr a, tr b){
    return a.x < b.x;
}

ll h,w,n;
vector<tr> a;

main(){
    cin >> h >> w >> n;
    ll f1,f2;
    a.resize(n);
    for(int i=0;i<n;++i){
        cin >> f1 >> f2;
        a[i] = {f1,f2};
    }
    sort(a.begin(),a.end());

    set<pair<ll,ll>> no_points;
    ll ans = h;
    for(int i=0;i<n;++i){
        if(no_points.count({a[i].x,a[i].y}) == 0 && a[i].x-1>=a[i].y){
            ans = a[i].x-1;
            //cout << "ans_p" << a[i].x << ' ' << a[i].y << "\n";
            break;
        }
        else{
            for(int j=0;j<min(min(ll(750),h-a[i].x),w-a[i].y);++j){
                //cout << a[i].x+j+1 << ' ' << a[i].y+j << "\n";
                if(no_points.count({a[i].x+j+1,a[i].y+j})){
                    break;
                }
                no_points.insert({a[i].x+j+1,a[i].y+j});
            }
            for(int j=max(0,h-750);j<min(min(ll(750),h-a[i].x),w-a[i].y);++j){
                //cout << a[i].x+j+1 << ' ' << a[i].y+j << "\n";
                if(no_points.count({a[i].x+j+1,a[i].y+j})){
                    break;
                }
                no_points.insert({a[i].x+j+1,a[i].y+j});
            }
        }
    }

    cout << ans;

}


Compiler output:
a.cc:16:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   16 | main(){
      | ^~~~
a.cc: In function 'int main()':
a.cc:42:26: error: no matching function for call to 'max(int, ll)'
   42 |             for(int j=max(0,h-750);j<min(min(ll(750),h-a[i].x),w-a[i].y);++j){
      |                       ~~~^~~~~~~~~
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:42:26: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'll' {aka 'long long int'})
   42 |             for(int j=max(0,h-750);j<min(min(ll(750),h-a[i].x),w-a[i].y);++j){
      |                       ~~~^~~~~~~~~
/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:42:26: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   42 |             for(int j=max(0,h-750);j<min(min(ll(750),h-a[i].x),w-a[i].y);++j){
      |                       ~~~^~~~~~~~~