Language: C++

bool DBG = false;
// #pragma GCC optimize("Ofast")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
// #pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
//#include <boost/multiprecision/cpp_dec_float.hpp>
//#include <boost/multiprecision/cpp_int.hpp>
using namespace std;
using ll = long long;
using ld = long double;
using i128 = __int128_t;
//using bint = boost::multiprecision::cpp_int;
//using d1024 = boost::multiprecision::number<mp::cpp_dec_float<1024>>;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define IFOR(i,a,b) for(int i=((b)-1);i>=(a);--i)
#define RPT(i,a,b) for(int i=(a);i<((a)+(b));++i)
#define IRPT(i,a,b) for(int i=((a)+(b)-1);i>=(a);--i)
#define ALL(x) x.begin(),x.end()
#define RALL(x) x.rbegin(),x.rend()
#define fs first
#define sd second
#define couts(x) cout << (x) << (" ")
#define coutn(x) cout << (x) << ("\n")
#define ncouts(x) numout(x),outst[outst_N++] = ' '
#define ncoutn(x) numout(x),outst[outst_N++] = '\n'
#define scouts(x) strout(x),outst[outst_N++] = ' '
#define scoutn(x) strout(x),outst[outst_N++] = '\n'
#define dcouts(x) if(DBG) couts(x)
#define dcoutn(x) if(DBG) coutn(x)
#define endl "\n"
#define psb push_back
#define ppb pop_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define LBIT(x,a) (((x)>>(a))&1LL)
#define IBIT(x,a) (((x)>>(a))&1)
#define BCOUNT(x) (__builtin_popcount(x))
template<typename T> std::istream &operator>>(std::istream &is, std::vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
template<typename T1, typename T2> std::istream &operator>>(std::istream &is, std::pair<T1,T2> &p){is >> p.first >> p.second; return is; }
template<typename T> std::ostream &operator<<(std::ostream &os, const std::vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> std::ostream &operator<<(std::ostream &os, const std::deque<T> &vec){ os << "deque["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> std::ostream &operator<<(std::ostream &os, const std::set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> std::ostream &operator<<(std::ostream &os, const std::unordered_set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> std::ostream &operator<<(std::ostream &os, const std::multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> std::ostream &operator<<(std::ostream &os, const std::unordered_multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T1, typename T2> std::ostream &operator<<(std::ostream &os, const std::pair<T1, T2> &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; }
template<typename TK, typename TV> std::ostream &operator<<(std::ostream &os, const std::map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename TK, typename TV> std::ostream &operator<<(std::ostream &os, const std::unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }

std::ostream &operator<<(std::ostream &os, const i128 nu){
  i128 co = nu;
  if(co==0){cout << '0';}
  else{
    string ous; if(co<0){cout<<'-'; co*=-1;}
    while(co){
      ous += (co%10)+'0';
      co /= 10;
    }
    reverse(ALL(ous));
    cout<<ous;
  }
  return os;
}
std::istream &operator>>(std::istream &is, i128 &nu){ string cs; cin >> cs; nu=0;int mn=1; for(auto &x:cs) { if(x!='-'){nu*=10;nu+=(x-'0');} else mn *= -1;} nu *= mn;  return is; }




template<class T> using V = vector<T>;
template<class T> using V2 = V<V<T>>;
template<class T> using V3 = V<V2<T>>;
template<class T> using V4 = V<V3<T>>;


char outst[20'000'000]; int outst_N = 0;
char outst_tmp[200];
template<class NUM >
void numout(NUM n){
  if(n<0) { n*=-1; outst[outst_N++] = '-';}
  if(n==0){ outst[outst_N++] = '0'; return;}
  int cnt = 0;
  while(n>0){
    outst_tmp[cnt++] = '0' + (n % 10);
    n /= 10;
  }
  IFOR(i,0,cnt){
    outst[outst_N++] = outst_tmp[i];
  }
}
void strout(std::string s){
  for(auto x: s){
    outst[outst_N++] = x;
  }
}

constexpr ll LINF = 1LL << 60;
constexpr int IINF = 1 << 28;
constexpr ll mod =  1'000'000'007;
//constexpr ll mod = 998244353;
template< class T>
bool isin(T L, T R, T N){
  return ( (N>=L) && (N<R) );
}

void solve(){
  int q; cin >> q;
  FOR(_,0,q){
    ll a, b; cin >> a >> b;
    i128 st = a*b; 
    ll l = 0, r = 1'000'000'000'000'000'000LL, ml;
    i128 m;
    while(r-l>1){
      m = (l+r)/2;
      ml = (l+r)/2;
      i128 K = -LINF;
      auto g = [&](ll L, ll R, ll arg)->i128{
        i128 ret = -LINF;
        if( isin<ll>(L,R,L) ) ret = max<i128>(ret, (i128)L*(i128)(arg-L) );
        if( isin<ll>(L,R,R-1) ) ret = max<i128>(ret, (i128)(R-1)*(i128)(arg-(R-1)) );
        FOR(i,-2,3){
          if( isin<ll>(L,R,arg/2+i) ) ret = max<i128>(ret, (i128)(arg/2+i)*(i128)(arg-(arg/2+i)) );
        }
        return ret;
      };
      auto f = [&](){
        K = max(K, g(1,min(a,ml+1-b),ml+1 ));
        K = max(K, g(1,min(b,ml+1-a),ml+1 ));
        K = max(K, g(min(a,ml+1-b),a,ml ));
        K = max(K, g(min(b,ml+1-a),b,ml ));
        return;
      };
      f();
      if(K<st) l = m;
      else r = m;
    }
    coutn(max(0,l-1));
  }
  
}






int main(void){
  //std::cout << std::fixed << std::setprecision(20);
  cin.tie(0);
  //ios::sync_with_stdio(false);
  solve();
  printf("%s", outst);
  return 0;
}




Compiler output:
a.cc: In function 'void solve()':
a.cc:137:14: error: no matching function for call to 'max(int, ll)'
  137 |     coutn(max(0,l-1));
      |           ~~~^~~~~~~
a.cc:23:27: note: in definition of macro 'coutn'
   23 | #define coutn(x) cout << (x) << ("\n")
      |                           ^
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:5:
/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:137:14: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'll' {aka 'long long int'})
  137 |     coutn(max(0,l-1));
      |           ~~~^~~~~~~
a.cc:23:27: note: in definition of macro 'coutn'
   23 | #define coutn(x) cout << (x) << ("\n")
      |                           ^
/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:137:14: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
  137 |     coutn(max(0,l-1));
      |           ~~~^~~~~~~
a.cc:23:27: note: in definition of macro 'coutn'
   23 | #define coutn(x) cout << (x) << ("\n")
      |                           ^