卡常技巧
Fast MOD
struct FastMod {
typedef __uint128_t lll;
ull b,m;
void init(ull b) {this->b=b,m=(ull)((lll(1)<<64)/b);}
ull operator()(ull a) {
ull q=(ull)((lll(m)*a)>>64),r=a-q*b;
return r>=b?r-b:r;
}
}M;Fast IO
完全阉割版：
namespace FastIO {
const int SIZE=1<<16; char buf[SIZE], obuf[SIZE], str[64]; int bi=SIZE, bn=SIZE, opt;
int read(char *s) {
while (bn) {for (;bi<bn&&buf[bi]<=' ';bi++);if (bi<bn) break; bn=fread(buf,1,SIZE,stdin),bi=0;}
int sn=0;while (bn) {for (;bi<bn&&buf[bi]>' ';bi++) s[sn++]=buf[bi];if (bi<bn) break; bn=fread(buf,1,SIZE,stdin),bi=0;}s[sn]=0;return sn;
}
bool read(int& x) {if(x)x=0;int bf=0,n=read(str); if(!n)return 0; int i=0; if (str[i]=='-') bf=1,i=1; for(x=0;i<n;i++) x=x*10+str[i]-'0'; if(bf) x=-x; return 1;}
void write(int x) {
if(!x) obuf[opt++] = '0'; else {if(x<0) obuf[opt++]='-',x=-x;int sn=0; while(x)str[sn++]=x%10+'0',x/=10;for (int i=sn-1;i>=0;i--) obuf[opt++]=str[i];}
if (opt>=(SIZE>>1)){fwrite(obuf, 1, opt, stdout); opt=0;}
}
void write(char x) {obuf[opt++]=x;if (opt>=(SIZE>>1)){fwrite(obuf, 1, opt, stdout); opt=0;}}
void Fflush() { if (opt) fwrite(obuf, 1, opt, stdout); opt=0;}
};相对完整版：
#define FI(n) FastIO::read(n)
#define FO(n) FastIO::write(n)
#define Flush FastIO::Fflush()
namespace FastIO {
const int SIZE = 1 << 16;
char buf[SIZE], obuf[SIZE], str[60];
int bi = SIZE, bn = SIZE, opt;
double D[] = {0.1, 0.01, 0.001, 0.0001, 0.00001, 0.000001, 0.0000001, 0.00000001, 0.000000001, 0.0000000001};
int read(char *s) {
while (bn) {
for (; bi < bn && buf[bi] <= ' '; bi++);
if (bi < bn) break;
bn = fread(buf, 1, SIZE, stdin);
bi = 0;
}
int sn = 0;
while (bn) {
for (; bi < bn && buf[bi] > ' '; bi++) s[sn++] = buf[bi];
if (bi < bn) break;
bn = fread(buf, 1, SIZE, stdin);
bi = 0;
}
s[sn] = 0;
return sn;
}
bool read(int& x) {
if(x) x = 0;
int n = read(str), bf = 0;
if (!n) return 0;
int i = 0; if (str[i] == '-') bf = 1, i++; else if (str[i] == '+') i++;
for (x = 0; i < n; i++) x = x * 10 + str[i] - '0';
if (bf) x = -x;
return 1;
}
bool read(long long& x) {
if(x) x = 0;
int n = read(str), bf;
if (!n) return 0;
int i = 0; if (str[i] == '-') bf = -1, i++; else bf = 1;
for (x = 0; i < n; i++) x = x * 10 + str[i] - '0';
if (bf < 0) x = -x;
return 1;
}
void write(int x) {
if (x == 0) obuf[opt++] = '0';
else {
if (x < 0) obuf[opt++] = '-', x = -x;
int sn = 0;
while (x) str[sn++] = x % 10 + '0', x /= 10;
for (int i = sn - 1; i >= 0; i--) obuf[opt++] = str[i];
}
if (opt >= (SIZE >> 1)) {
fwrite(obuf, 1, opt, stdout);
opt = 0;
}
}
void write(long long x) {
if (x == 0) obuf[opt++] = '0';
else {
if (x < 0) obuf[opt++] = '-', x = -x;
int sn = 0;
while (x) str[sn++] = x % 10 + '0', x /= 10;
for (int i = sn - 1; i >= 0; i--) obuf[opt++] = str[i];
}
if (opt >= (SIZE >> 1)) {
fwrite(obuf, 1, opt, stdout);
opt = 0;
}
}
void write(unsigned long long x) {
if (x == 0) obuf[opt++] = '0';
else {
int sn = 0;
while (x) str[sn++] = x % 10 + '0', x /= 10;
for (int i = sn - 1; i >= 0; i--) obuf[opt++] = str[i];
}
if (opt >= (SIZE >> 1)) {
fwrite(obuf, 1, opt, stdout);
opt = 0;
}
}
void write(char x) {
obuf[opt++] = x;
if (opt >= (SIZE >> 1)) {
fwrite(obuf, 1, opt, stdout);
opt = 0;
}
}
void Fflush() { if (opt) fwrite(obuf, 1, opt, stdout); opt = 0;}
};自2020.7.22起的代码缺省源：
#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define mkp make_pair
#define si set < int >
#define vi vector < int >
#define pii pair < int, int >
#define mii map < int, int >
#define p_q priority_queue
#define INF ((1 << 30) - 1)
#define FI(n) FastIO::read(n)
#define FO(n) FastIO::write(n)
#define ull unsigned long long
#define mst(a, b) memset(a,b,sizeof(a))
#define foR(i, k, j) for(int i = (k); i >= (j); i--)
#define For(i, k, j) for(int i = (k); i <= (j); i++)
#define Foe(i, u) for(int i = lst[u], v = e[i].v; i; i = e[i].nxt, v = e[i].v)
#define IOS ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define Fin(s) freopen(s, "r", stdin)
#define Fout(s) freopen(s, "w", stdout)
#define file(s) Fin(s".in"), Fout(s".out")
//#define int long long
const int P = 998244353; //
using namespace std;
template <typename T> inline void ckmax(T &a, T b) {(a < b) && (a = b);}
template <typename T> inline void ckmin(T &a, T b) {(a > b) && (a = b);}
inline int mul(int a, int b) {return 1ll * a * b % P;}
inline int add(int a, int b) {return a + b >= P ? a + b - P : a + b;}
inline int sub(int a, int b) {return a - b >= 0 ? a - b : a - b + P;}
inline void mulmod(int &a, int b) {a = mul(a, b);}
inline void addmod(int &a, int b) {((a += b) >= P) && (a -= P);}
inline void submod(int &a, int b) {((a -= b) < 0) && (a += P);}
inline int ksm(int a, int b) {int ans=1; for(;b;b>>=1) {if(b&1) ans=1ll*ans*a%P;a=1ll*a*a%P;}return ans;}
inline int inv(int a) {return ksm(a, P-2);}
namespace FastIO {
const int SIZE=1<<16; char buf[SIZE], obuf[SIZE], str[64]; int bi=SIZE, bn=SIZE, opt;
int read(char *s) {
while (bn) {for (;bi<bn&&buf[bi]<=' ';bi++);if (bi<bn) break; bn=fread(buf,1,SIZE,stdin),bi=0;}
int sn=0;while (bn) {for (;bi<bn&&buf[bi]>' ';bi++) s[sn++]=buf[bi];if (bi<bn) break; bn=fread(buf,1,SIZE,stdin),bi=0;}s[sn]=0;return sn;
}
bool read(int& x) {if(x)x=0;int bf=0,n=read(str); if(!n) return 0; int i=0; if (str[i]=='-') bf=1,i=1; for(x=0;i<n;i++) x=x*10+str[i]-'0'; if(bf) x=-x; return 1;}
void write(int x) {
if(!x) obuf[opt++] = '0'; else {if(x<0) obuf[opt++]='-',x=-x;int sn=0; while(x)str[sn++]=x%10+'0',x/=10;for (int i=sn-1;i>=0;i--) obuf[opt++]=str[i];}
if (opt>=(SIZE>>1)){fwrite(obuf, 1, opt, stdout); opt=0;}
}
void write(char x) {obuf[opt++]=x;if (opt>=(SIZE>>1)){fwrite(obuf, 1, opt, stdout); opt=0;}}
void Fflush() { if (opt) fwrite(obuf, 1, opt, stdout); opt=0;}
};
inline int read() {int x; FI(x); return x;}
signed main()
{
#ifndef ONLINE_JUDGE
file("pro");
#endif
return FastIO::Fflush(), 0;
}
/*
*/
#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define mkp make_pair
#define si set < int >
#define vi vector < int >
#define pii pair < int, int >
#define mii map < int, int >
#define p_q priority_queue
#define INF ((1 << 30) - 1)
#define FI(n) FastIO::read(n)
#define FO(n) FastIO::write(n)
#define ull unsigned long long
#define mst(a, b) memset(a,b,sizeof(a))
#define foR(i, k, j) for(int i = (k); i >= (j); i--)
#define For(i, k, j) for(int i = (k); i <= (j); i++)
#define Foe(i, u) for(int i = lst[u], v = e[i].v; i; i = e[i].nxt, v = e[i].v)
#define IOS ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define Fin(s) freopen(s, "r", stdin)
#define Fout(s) freopen(s, "w", stdout)
#define file(s) Fin(s".in"), Fout(s".out")
//#define int long long
const int P=998244353; //
using namespace std;
template<typename T>inline void ckmax(T &a,T b) {(a<b)&&(a=b);}
template<typename T>inline void ckmin(T &a,T b) {(a>b)&&(a=b);}
inline int mul(int a,int b) {return 1ll*a*b%P;}
inline int add(int a,int b) {return a+b>=P?a+b-P:a+b;}
inline int sub(int a,int b) {return a-b>=0?a-b:a-b+P;}
inline void mulmod(int &a,int b) {a=mul(a, b);}
inline void addmod(int &a,int b) {((a+=b)>=P)&&(a-=P);}
inline void submod(int &a,int b) {((a-=b)<0)&&(a+=P);}
inline int ksm(int a, int b) {int ans=1; for(;b;b>>=1) {if(b&1) ans=1ll*ans*a%P;a=1ll*a*a%P;}return ans;}
inline int inv(int a) {return ksm(a, P-2);}
namespace FastIO {
const int SIZE=1<<16; char buf[SIZE],obuf[SIZE],str[64]; int bi=SIZE,bn=SIZE,opt;
int read(char *s) {
while (bn) {for (;bi<bn&&buf[bi]<=' ';bi++);if (bi<bn) break; bn=fread(buf,1,SIZE,stdin),bi=0;}
int sn=0;while (bn) {for (;bi<bn&&buf[bi]>' ';bi++) s[sn++]=buf[bi];if (bi<bn) break; bn=fread(buf,1,SIZE,stdin),bi=0;}s[sn]=0;return sn;
}
bool read(int& x) {if(x)x=0;int bf=0,n=read(str); if(!n) return 0; int i=0; if (str[i]=='-') bf=1,i=1; for(x=0;i<n;i++) x=x*10+str[i]-'0'; if(bf) x=-x; return 1;}
void write(int x) {
if(!x) obuf[opt++] = '0'; else {if(x<0) obuf[opt++]='-',x=-x;int sn=0; while(x)str[sn++]=x%10+'0',x/=10;for (int i=sn-1;i>=0;i--) obuf[opt++]=str[i];}
if (opt>=(SIZE>>1)){fwrite(obuf, 1, opt, stdout); opt=0;}
}
void write(char x) {obuf[opt++]=x;if (opt>=(SIZE>>1)){fwrite(obuf, 1, opt, stdout); opt=0;}}
void Fflush() { if (opt) fwrite(obuf, 1, opt, stdout); opt=0;}
};
inline int read() {int x; FI(x); return x;}
int main() {
#ifndef ONLINE_JUDGE
freopen("pro.in","r",stdin);
freopen("pro.out","w",stdout);
#endif
return FastIO::Fflush(),0;
}
## 火车头
```cpp
#define _CRT_SECURE_NO_WARNINGS
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-fwhole-program")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-fstrict-overflow")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-skip-blocks")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("-funsafe-loop-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")