Language: C++

#include <bits/stdc++.h>
using namespace std;
#ifndef ONLINE_JUDGE
	#include <boost/multiprecision/cpp_int.hpp>
	#include <boost/multiprecision/cpp_dec_float.hpp>
	using bll = boost::multiprecision::cpp_int;
	using bdouble = boost::multiprecision::cpp_dec_float_100;
#endif
#ifdef LOCAL_DEV
	void debug_impl() { std::cerr << std::endl; }
	template<typename Head, typename... Tail> void debug_impl(Head head, Tail... tail) { std::cerr << " " << head << (sizeof...(tail) ? "," : ""); debug_impl(tail...); }
	#define debug(...) std::cerr << std::boolalpha << "(" << #__VA_ARGS__ << ") ="; debug_impl(__VA_ARGS__); std::cerr << std::noboolalpha;
#else
	#define debug(...)
#endif
#ifdef LOCAL_TEST
	#define BOOST_STACKTRACE_USE_ADDR2LINE
	#define BOOST_STACKTRACE_ADDR2LINE_LOCATION /usr/local/opt/binutils/bin/addr2line
	#define _GNU_SOURCE
	#include <boost/stacktrace.hpp>
	template<typename T> class dvector : public std::vector<T> {
	public:
		dvector() : std::vector<T>() {}
		explicit dvector(size_t n, const T& value = T()) : std::vector<T>(n, value) {}
		dvector(const std::vector<T>& v) : std::vector<T>(v) {}
		dvector(const std::initializer_list<T> il) : std::vector<T>(il) {}
		dvector(const typename std::vector<T>::iterator first, const typename std::vector<T>::iterator last) : std::vector<T>(first, last) {}
		dvector(const std::string::iterator first, const std::string::iterator last) : std::vector<T>(first, last) {}
		T& operator[](size_t n) {
			try { return this->at(n); } catch (const std::exception& e) {
				std::cerr << boost::stacktrace::stacktrace() << std::endl; return this->at(n);
			}
		}
		const T& operator[](size_t n) const {
			try { return this->at(n); } catch (const std::exception& e) {
				std::cerr << boost::stacktrace::stacktrace() << std::endl; return this->at(n);
			}
		}
	};
	class dbool {
	private:
		bool boolvalue;
	public:
		dbool() : boolvalue(false) {}
		dbool(bool b) : boolvalue(b) {}
		dbool(const dbool &b) : boolvalue(b.boolvalue) {}
		operator bool&() { return boolvalue; }
		operator const bool&() const { return boolvalue; }
	};
	template<typename T> std::ostream& operator<<(std::ostream& s, const dvector<T>& v) {
		for (int i = 0, len = v.size(); i < len; ++i){ s << v[i]; if (i < len - 1) s << "\t"; } return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const dvector< dvector<T> >& vv) {
		for (int i = 0, len = vv.size(); i < len; ++i){ s << vv[i] << std::endl; } return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::set<T>& se) {
		s << "{ "; for (auto itr = se.begin(); itr != se.end(); ++itr){ s << (*itr) << "\t"; } s << "}" << std::endl; return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::multiset<T>& se) {
		s << "{ "; for (auto itr = se.begin(); itr != se.end(); ++itr){ s << (*itr) << "\t"; } s << "}" << std::endl; return s; }
	template<typename T1, typename T2> std::ostream& operator<<(std::ostream& s, const std::map<T1, T2>& m) {
		s << "{" << std::endl; for (auto itr = m.begin(); itr != m.end(); ++itr){ s << "\t" << (*itr).first << " : " << (*itr).second << std::endl; } s << "}" << std::endl; return s; }
	template<typename T1, typename T2> std::ostream& operator<<(std::ostream& s, const std::pair<T1, T2>& p) { 
		return s << "(" << p.first << ", " << p.second << ")"; }
	#define vector dvector
	#define bool dbool
#endif
//#define int long long
using ll = long long;
//constexpr int INF = 1e9;//INT_MAX=(1<<31)-1=2147483647
constexpr ll INF = (ll)1e18;//(1LL<<63)-1=9223372036854775807
constexpr ll MOD = (ll)1e9 + 7;
constexpr double EPS = 1e-9;
constexpr int dx[4]={1,0,-1,0};
constexpr int dy[4]={0,1,0,-1};
#define p(var) std::cout<<var<<std::endl
#define rep(i, n)   for(ll i=0, i##_length=(n); i< i##_length; ++i)
#define repeq(i, n) for(ll i=1, i##_length=(n); i<=i##_length; ++i)
#define all(v) (v).begin(), (v).end()
#define uniq(v) (v).erase(unique((v).begin(), (v).end()), (v).end());
template<typename T> inline void pv(vector<T> &v) { for(ll i=0, N=v.size(); i<N; i++) std::cout << v[i] << " \n"[i==N-1]; }
template<typename T> inline T gcd(T a, T b) { return b ? gcd(b,a%b) : a; }
template<typename T> inline T lcm(T a, T b) { return a / gcd(a,  b) * b; }
template<typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template<typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

/*-----8<-----template-----8<-----*/

class TwoDImos {
public:
	//vectorの要素数
	ll H, W;
	//[Lx[i], Rx[i]) x [Ly[i], Ry[i])の範囲に1を加算する
	vector<ll> Lx, Rx, Ly, Ry;
	//累積和したvector
	vector<vector<ll>> rui;

	TwoDImos(ll H, ll W, vector<ll> &Lx, vector<ll> &Rx, vector<ll> &Ly, vector<ll> &Ry)
	 : H(H), W(W), Lx(Lx), Rx(Rx) , Ly(Ly), Ry(Ry) {
		assert(Lx.size() == Rx.size());
		assert(Ly.size() == Ry.size());
		assert(Lx.size() == Ly.size());
		rui.assign(H, vector<ll>(W, 0));
		build();
	}

	TwoDImos(ll H, ll W, vector<tuple<ll, ll, ll, ll>> &range) : H(H), W(W) {
		rui.assign(H, vector<ll>(W, 0));
		ll rsize = range.size();
		Lx.assign(rsize, 0);
		Rx.assign(rsize, 0);
		Ly.assign(rsize, 0);
		Ry.assign(rsize, 0);
		for (ll i = 0; i < rsize; ++i) {
			tie(Lx[i], Rx[i], Ly[i], Ry[i]) = range[i];
		}
		build();
	}

	void build(){
		// 重みの加算
		for (ll i = 0, N = Lx.size(); i < N; ++i) {
			rui[Lx[i]][Ly[i]]++;
			if(Rx[i] < H) rui[Rx[i]][Ly[i]]--;
			if(Ry[i] < W) rui[Lx[i]][Ry[i]]--;
			if(Rx[i] < H && Ry[i] < W) rui[Rx[i]][Ry[i]]++;
		}
		// 横方向への累積和
		for (ll i = 0; i < H; ++i) 
			for (ll j = 1; j < W; ++j) 
				rui[i][j] += rui[i][j-1];
		// 縦方向の累積和
		for (ll i = 1; i < H; ++i) 
			for (ll j = 0; j < W; ++j) 
				rui[i][j] += rui[i-1][j];		
	}

	// ruiの全域に対して関数fを適用した結果を返却する
	ll query(std::function<ll(ll, ll)> f) {
		ll val = rui[0][0];
		for (ll i = 0; i < H; ++i) 
			for (ll j = 0; j < W; ++j) 
				if(i || j) val = f(val, rui[i][j]);
		return val;
	}
};

/*-----8<-----library-----8<-----*/

signed main() {
	//https://atcoder.jp/contests/abc086/tasks/arc089_b
	ll N,K;
	cin>>N>>K;
	vector<ll> Lx(N,0), Rx(N,0), Ly(N,0), Ry(N,0);
	vector<tuple<ll, ll, ll, ll>> range;
	rep(i,N){
		ll x, y;
		char s;
		cin>>x>>y>>s;
		
		if (((x < K && y < K) || (x >= K && y >= K)) == (s == 'B')) {
			x%=K, y%=K;
			range.push_back({        0,     x + 1,         0,     y + 1});
			range.push_back({x + K + 1,     2 * K,         0,     y + 1});
			range.push_back({        0,     x + 1, y + K + 1,     2 * K});
			range.push_back({x + K + 1,     2 * K, y + K + 1,     2 * K});
			range.push_back({    x + 1, x + K + 1,     y + 1, y + K + 1});
		} else {
			x%=K, y%=K;
			range.push_back({    x + 1, x + K + 1,         0,     y + 1});
			range.push_back({    x + 1, x + K + 1, y + K + 1,     2 * K});
			range.push_back({        0,     x + 1,     y + 1, y + K + 1});
			range.push_back({x + K + 1,     2 * K,     y + 1, y + K + 1});
		}
	}

	TwoDImos imos(2*K+1, 2*K+1, range);
	//全域の最大値、全域の最小値、全域の総和
	auto maxlambda = [](ll x,ll y){return max(x,y);};
	//auto minlambda = [](ll x,ll y){return min(x,y);};
	//auto addlambda = [](ll x,ll y){return x+y;};
	ll maxval = imos.query(maxlambda);
	cout<<maxval<<endl;

	return 0;
}



Compiler output:
a.cc:4:18: fatal error: boost/multiprecision/cpp_int.hpp: No such file or directory
    4 |         #include <boost/multiprecision/cpp_int.hpp>
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.