快读

namespace Fread
{
	const int SIZE = 1 << 16;
	char buf[SIZE], *S, *T;
	inline char getchar() { if (S == T) { T = (S = buf) + fread(buf, 1, SIZE, stdin); if (S == T) return '\n'; } return *S++; }
}
using namespace Fread;
namespace Fwrite
{
	const int SIZE = 1 << 16;
	char buf[SIZE], *S = buf, *T = buf + SIZE;
	inline void flush() { fwrite(buf, 1, S - buf, stdout); S = buf; }
	inline void putchar(char c) { *S++ = c; if (S == T) flush(); }
	struct NTR { ~NTR() { flush(); } } ztr;
}
using namespace Fwrite;
#define getchar Fread::getchar
#define putchar Fwrite::putchar
namespace Fastio
{
	struct Reader
	{
		template <typename T> Reader& operator >> (T &x)
		{
			x = 0;
			short f = 1;
			char c = getchar();
			while (c < '0' || c > '9') { if (c == '-') f *= -1; c = getchar(); }
			while (c >= '0' && c <= '9') x = (x << 3) + (x << 1) + (c ^ 48), c = getchar();
			x *= f;
			return *this;
		}
		Reader& operator >> (double &x)
		{
			x = 0;
			double t = 0;
			short f = 1, s = 0;
			char c = getchar();
			while ((c < '0' || c > '9') && c != '.') { if (c == '-') f *= -1; c = getchar(); }
			while (c >= '0' && c <= '9' && c != '.') x = x * 10 + (c ^ 48), c = getchar();
			if (c == '.') c = getchar();
			else { x *= f; return *this; }
			while (c >= '0' && c <= '9') t = t * 10 + (c ^ 48), s++, c = getchar();
			while (s--) t /= 10.0;
			x = (x + t) * f;
			return *this;
		}
		Reader& operator >> (long double &x)
		{
			x = 0;
			long double t = 0;
			short f = 1, s = 0;
			char c = getchar();
			while ((c < '0' || c > '9') && c != '.') { if (c == '-') f *= -1; c = getchar(); }
			while (c >= '0' && c <= '9' && c != '.') x = x * 10 + (c ^ 48), c = getchar();
			if (c == '.') c = getchar();
			else { x *= f; return *this; }
			while (c >= '0' && c <= '9') t = t * 10 + (c ^ 48), s++, c = getchar();
			while (s--) t /= 10.0;
			x = (x + t) * f;
			return *this;
		}
		Reader& operator >> (__float128 &x)
		{
			x = 0;
			__float128 t = 0;
			short f = 1, s = 0;
			char c = getchar();
			while ((c < '0' || c > '9') && c != '.') { if (c == '-') f *= -1; c = getchar(); }
			while (c >= '0' && c <= '9' && c != '.') x = x * 10 + (c ^ 48), c = getchar();
			if (c == '.') c = getchar();
			else { x *= f; return *this; }
			while (c >= '0' && c <= '9') t = t * 10 + (c ^ 48), s++, c = getchar();
			while (s--) t /= 10.0;
			x = (x + t) * f;
			return *this;
		}
		Reader& operator >> (char &c)
		{
			c = getchar();
			while (c == ' ' || c == '\n' || c == '\r') c = getchar();
			return *this;
		}
		Reader& operator >> (char *str)
		{
			int len = 0;
			char c = getchar();
			while (c == ' ' || c == '\n' || c == '\r') c = getchar();
			while (c != ' ' && c != '\n' && c != '\r') str[len++] = c, c = getchar();
			str[len] = '\0';
			return *this;
		}
		Reader& operator >> (string &str)
		{
			str.clear();
			char c = getchar();
			while (c == ' ' || c == '\n' || c == '\r') c = getchar();
			while (c != ' ' && c != '\n' && c != '\r') str.push_back(c), c = getchar();
			return *this;
		}
		Reader() {}
	} cin;
	const char endl = '\n';
	struct Writer
	{
		const int Setprecision = 6;
		typedef int mxdouble;
		template <typename T> Writer& operator << (T x)
		{
			if (x == 0) { putchar('0'); return *this; }
			if (x < 0) putchar('-'), x = -x;
			static short sta[40];
			short top = 0;
			while (x > 0) sta[++top] = x % 10, x /= 10;
			while (top > 0) putchar(sta[top] + '0'), top--;
			return *this;
		}
		Writer& operator << (double x)
		{
			if (x < 0) putchar('-'), x = -x;
			mxdouble _ = x;
			x -= (double)_;
			static short sta[40];
			short top = 0;
			while (_ > 0) sta[++top] = _ % 10, _ /= 10;
			if (top == 0) putchar('0');
			while (top > 0) putchar(sta[top] + '0'), top--;
			putchar('.');
			for (int i = 0; i < Setprecision; i++) x *= 10;
			_ = x;
			while (_ > 0) sta[++top] = _ % 10, _ /= 10;
			for (int i = 0; i < Setprecision - top; i++) putchar('0');
			while (top > 0) putchar(sta[top] + '0'), top--;
			return *this;
		}
		Writer& operator << (long double x)
		{
			if (x < 0) putchar('-'), x = -x;
			mxdouble _ = x;
			x -= (long double)_;
			static short sta[40];
			short top = 0;
			while (_ > 0) sta[++top] = _ % 10, _ /= 10;
			if (top == 0) putchar('0');
			while (top > 0) putchar(sta[top] + '0'), top--;
			putchar('.');
			for (int i = 0; i < Setprecision; i++) x *= 10;
			_ = x;
			while (_ > 0) sta[++top] = _ % 10, _ /= 10;
			for (int i = 0; i < Setprecision - top; i++) putchar('0');
			while (top > 0) putchar(sta[top] + '0'), top--;
			return *this;
		}
		Writer& operator << (__float128 x)
		{
			if (x < 0) putchar('-'), x = -x;
			mxdouble _ = x;
			x -= (__float128)_;
			static short sta[40];
			short top = 0;
			while (_ > 0) sta[++top] = _ % 10, _ /= 10;
			if (top == 0) putchar('0');
			while (top > 0) putchar(sta[top] + '0'), top--;
			putchar('.');
			for (int i = 0; i < Setprecision; i++) x *= 10;
			_ = x;
			while (_ > 0) sta[++top] = _ % 10, _ /= 10;
			for (int i = 0; i < Setprecision - top; i++) putchar('0');
			while (top > 0) putchar(sta[top] + '0'), top--;
			return *this;
		}
		Writer& operator << (char c) { putchar(c); return *this; }
		Writer& operator << (char *str)
		{
			int cur = 0;
			while (str[cur]) putchar(str[cur++]);
			return *this;
		}
		Writer& operator << (const char *str)
		{
			int cur = 0;
			while (str[cur]) putchar(str[cur++]);
			return *this;
		}
		Writer& operator << (string str)
		{
			int st = 0, ed = str.size();
			while (st < ed) putchar(str[st++]);
			return *this;
		}
		Writer() {}
	} cout;
}
using namespace Fastio;
#define cin Fastio::cin
#define cout Fastio::cout
#define endl Fastio::endl

具体使用方法说起来需要用到面向对象相关编程知识，会使本篇题解失去重心，所以请自行查阅资料或者询问 AI。