我的板子

读写优化

优化一

#ifdef _WIN32
	#define getchar _getchar_nolock
	#define putchar _putchar_nolock
#else
	#define getchar getchar_unlocked
	#define putchar putchar_unlocked
#endif
template <typename T> inline void rd(T &x){
	x = 0; int f = 1; char ch = getchar();
	while(!isdigit(ch)){ if(ch == '-') f = -1; ch = getchar();}
	while(isdigit(ch)) x = (x<<1) + (x<<3) + (ch^48), ch = getchar();
	x *= f;
}
template <typename T> inline void wt(T x){
	if(x < 0) putchar('-'), x = -x;
	if(x / 10 > 0) wt(x / 10); putchar(x % 10 + '0');
}

优化二

constexpr int B = 1 << 20;
char buf[B], *p1 = buf, *p2 = buf, obuf[B], *O = obuf;
#define gt() (p1==p2 && (p2=(p1=buf)+fread(buf, 1, B, stdin), p1==p2) ? EOF : *p1++)
template <typename T> inline void rd(T &x){
	x = 0; int f = 0; char ch = gt();
	for(; !isdigit(ch); ch = gt()) f ^= ch == '-';
	for(; isdigit(ch); ch = gt()) x = (x<<1) + (x<<3) + (ch^48);
	x = f ? -x : x;
}
#define pt(ch) (O-obuf==B && (fwrite(obuf, 1, B, stdout), O=obuf), *O++ = (ch))
template <typename T> inline void wt(T x){
	if(x < 0) pt('-'), x = -x;
	if(x > 9) wt(x / 10); pt(x % 10 ^ 48);
}
#define fw fwrite(obuf, 1, O - obuf, stdout)

注意在代码末尾加上 fw

fwrite(obuf, 1, O - obuf, stdout)

取模

inline int mod(int x){ return (x % M + M) % M; }
inline int mul(initializer_list<int> Mul){
	int res = 1;
	for(int v : Mul) res = (ll)res * v % M;
	return res;
}
inline void add(initializer_list<int> Add){
	int res = 1;
	for(int v : Add) res = res + v > M ? res + v - M : res + v;
	return res;
}

用的时候写个大括号直接往里写上所有数即可：like：

int ans = mul({2, 3, 500000004});
int res = add({1, 2, 3, 4, 5, 6});
int okk = mod(-114514);

取模加速

// generated by Copilot
#include <iostream>
 
class BarrettModulo {
private:
    uint64_t p; // The modulus
    uint64_t m; // Precomputed value for optimization
 
public:
    BarrettModulo(uint64_t modulus) : p(modulus) {
        m = ((__int128)1 << 64) / p;
    }
 
    uint64_t operator()(uint64_t x) const {
        return x - ((__int128(x) * m) >> 64) * p;
    }
};
 
int main() {
    BarrettModulo Mod(998244353);
    uint64_t result = Mod(998244354);
 
    std::cout << "Result: " << result << std::endl;
 
    return 0;
}