Language: C++

#include <bits/stdc++.h>
#define ll long long
#define INF 999999999
#define MOD 1000000007
#define rep(i,n) for(int i=0;i<n;i++)

using namespace std;

typedef pair<int,int>P;

const int MAX_N = 100005;

int a[MAX_N];
map<P,int> mx,my;
set<P> sx,sy;
set<int> ss;
int x[MAX_N],y[MAX_N];

void dfs(int v)
{
	ss.insert(v);
	sx.erase(sx.find(P(x[v],y[v])));
	sy.erase(sy.find(P(y[v],x[v])));
	P cur,end;
	//left
	cur = P(x[v]-d,y[v]-d);
	end = P(x[v]-d,y[v]+d);
	while(1){
		auto it = sx.lower_bound(cur);
		if(it = sx.end() || (*it) > end){
			break;
		}
		cur = *it;
		dfs(mx[cur]);
	}
	//right
	cur = P(x[v]+d,y[v]-d);
	end = P(x[v]+d,y[v]+d);
	while(1){
		auto it = sx.lower_bound(cur);
		if(it = sx.end() || (*it) > end){
			break;
		}
		cur = *it;
		dfs(mx[cur]);
	}
	//up
	cur = P(x[v]-d,y[v]-d);
	end = P(x[v]-d,y[v]+d);
	while(1){
		auto it = sx.lower_bound(cur);
		if(it = sy.end() || (*it) > end){
			break;
		}
		cur = *it;
		dfs(mx[cur]);
	}
	//down
	cur = P(x[v]+d,y[v]-d);
	end = P(x[v]+d,y[v]+d);
	while(1){
		auto it = sx.lower_bound(cur);
		if(it = sy.end() || (*it) > end){
			break;
		}
		cur = *it;
		dfs(mx[cur]);
	}
}	
	
int main()
{
	int n,a,b;
	scanf("%d%d%d",&n,&a,&b);
	int x,y,x[i],y[i];
	rep(i,n){
		scanf("%d%d",&x,&y);
		x[i] = x - y;
		y[i] = x + y;
		mx[P(x[i],y[i])] = i;
		my[P(y[i],x[i])] = i;
		sx.insert(P(x[i],y[i]));
		sy.insert(P(y[i],x[i]));
	}
	d = max(abs(x[a-1]-x[b-1]),abs(y[a-1]-y[b-1]));
	dfs(a-1);
	rep(i,n){
		vx.push_back(P(x[i],y[i]));
		vy.push_back(P(y[i],x[i]));
	}
	sort(vx.begin(),vx.end());
	sort(vy.begin(),vy.end());
	ll ans = 0;
	rep(v,ss.size()){
		P cur,end;
		//left
		cur = P(x[v]-d,y[v]-d);
		end = P(x[v]-d,y[v]+d);
		ans += vx.upper_bound(end) - vx.lower_bound(cur);
		//right
		cur = P(x[v]+d,y[v]-d);
		end = P(x[v]+d,y[v]+d);
		ans += vx.upper_bound(end) - vx.lower_bound(cur);
		//up
		cur = P(x[v]-d,y[v]-d);
		end = P(x[v]-d,y[v]+d);
		ans += vy.upper_bound(end) - vy.lower_bound(cur);
		//down
		cur = P(x[v]+d,y[v]-d);
		end = P(x[v]+d,y[v]+d);
		ans += vy.upper_bound(end) - vy.lower_bound(cur);
	}
	cout << ans / 2 << "\n";
}

Compiler output:
a.cc: In function 'void dfs(int)':
a.cc:26:22: error: 'd' was not declared in this scope
   26 |         cur = P(x[v]-d,y[v]-d);
      |                      ^
a.cc:30:34: error: no match for 'operator||' (operand types are 'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} and 'bool')
   30 |                 if(it = sx.end() || (*it) > end){
      |                         ~~~~~~~~ ^~ ~~~~~~~~~~~
      |                               |           |
      |                               |           bool
      |                               std::set<std::pair<int, int> >::iterator {aka std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator}
a.cc:30:34: note: candidate: 'operator||(bool, bool)' (built-in)
   30 |                 if(it = sx.end() || (*it) > end){
      |                         ~~~~~~~~~^~~~~~~~~~~~~~
a.cc:30:34: note:   no known conversion for argument 1 from 'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} to 'bool'
In file included from /usr/include/c++/14/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166,
                 from a.cc:1:
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:30:45: note:   'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   30 |                 if(it = sx.end() || (*it) > end){
      |                                             ^~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:30:45: note:   'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   30 |                 if(it = sx.end() || (*it) > end){
      |                                             ^~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:30:45: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'bool'
   30 |                 if(it = sx.end() || (*it) > end){
      |                                             ^~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:30:45: note:   'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   30 |                 if(it = sx.end() || (*it) > end){
      |                                             ^~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:30:45: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'bool'
   30 |                 if(it = sx.end() || (*it) > end){
      |                                             ^~~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const valarray<_Tp>&, const valarray<_Tp>&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:30:45: note:   'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} is not derived from 'const std::valarray<_Tp>'
   30 |                 if(it = sx.end() || (*it) > end){
      |                                             ^~~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:30:45: note:   'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} is not derived from 'const std::valarray<_Tp>'
   30 |                 if(it = sx.end() || (*it) > end){
      |                                             ^~~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:30:45: note:   mismatched types 'const std::valarray<_Tp>' and 'bool'
   30 |                 if(it = sx.end() || (*it) > end){
      |                                             ^~~
a.cc:41:34: error: no match for 'operator||' (operand types are 'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} and 'bool')
   41 |                 if(it = sx.end() || (*it) > end){
      |                         ~~~~~~~~ ^~ ~~~~~~~~~~~
      |                               |           |
      |                               |           bool
      |                               std::set<std::pair<int, int> >::iterator {aka std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator}
a.cc:41:34: note: candidate: 'operator||(bool, bool)' (built-in)
   41 |                 if(it = sx.end() || (*it) > end){
      |                         ~~~~~~~~~^~~~~~~~~~~~~~
a.cc:41:34: note:   no known conversion for argument 1 from 'std::set<std::pair<int, int> >::iterator' {aka 'std::_Rb_tree<std::pair<int, int>, std::pair<int, int>, std::_Identity<std::pair<int, int> >, std::less<std::pair<int, int> >, std::allocator<std::pair<int, int> > >::const_iterator'} to 'bool'
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom1, class _Dom2> s