sth useless

g++ -o2 -std=c++14 -o a a.cpp && ./a

#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2")

#include<bits/stdc++.h>
using namespace std;
namespace Fread{const int SIZE = (1 << 18);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++;}}
namespace Fwrite {const int SIZE = (1 << 18);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;}
#ifdef ONLINE_JUDGE
#define getchar Fread::getchar
#define putchar Fwrite::putchar
#endif
namespace Fastio{struct Reader{template <typename T>Reader&operator>>(T&x){char c=getchar();bool f=false;while (c<'0'||c>'9') { if(c == '-')f = true;c=getchar();}x=0;while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+(c^48);c=getchar();}if(f)x=-x;return *this;}Reader&operator>>(double & x) {char c=getchar();short f=1,s=0;x=0;double t=0;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 return x*=f,*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){char c=getchar();short f=1,s=0;x=0;long double t=0;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 return x*=f,*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){char c=getchar();short f=1,s=0;x=0;__float128 t=0;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 return x*=f, *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=='\n'||c==' '||c=='\r')c=getchar();return *this;}Reader&operator>>(char*str){int len=0;char c=getchar();while(c=='\n'||c==' '||c=='\r')c=getchar();while(c!='\n'&&c!=' '&&c!='\r')str[len++]=c,c=getchar();str[len]='\0';return *this;}Reader&operator>>(string&str){char c=getchar();str.clear();while(c=='\n'||c==' '||c=='\r')c=getchar();while(c!='\n'&&c!=' '&&c!='\r')str.push_back(c),c=getchar();return *this;}template<class _Tp>Reader&operator>>(vector<_Tp>&vec){for(unsigned i=0;i<vec.size();i++)cin>>vec[i];return *this;}template<class _Tp,class _tp>Reader&operator>>(pair<_Tp,_tp>&a){cin>>a.first>>a.second;return *this;}Reader(){}}cin;const char endl='\n';struct Writer{static const int set_precision = 6;typedef int mxdouble;template<typename T>Writer&operator<<(T x){if(x==0)return putchar('0'),*this;if(x<0)putchar('-'),x=-x;static int sta[45];int top=0;while(x)sta[++top]=x%10,x/=10;while(top)putchar(sta[top]+'0'),--top;return*this;}Writer&operator<<(double x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(double)_;static int sta[45];int top=0;while(_)sta[++top]=_%10,_/=10;if(!top)putchar('0');while(top)putchar(sta[top]+'0'),--top;putchar('.');for(int i=0;i<set_precision;i++)x*=10;_=x;while(_)sta[++top]=_%10,_/=10;for(int i=0;i<set_precision-top;i++)putchar('0');while(top)putchar(sta[top]+'0'),--top;return*this;}Writer&operator<<(long double x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(long double)_;static int sta[45];int top=0;while(_)sta[++top]=_%10,_/=10;if(!top)putchar('0');while(top)putchar(sta[top]+'0'),--top;putchar('.');for(int i=0;i<set_precision;i++)x*=10;_=x;while(_)sta[++top]=_%10,_/=10;for(int i=0;i<set_precision-top;i++)putchar('0');while(top)putchar(sta[top]+'0'),--top;return*this;}Writer&operator<<(__float128 x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(__float128)_;static int sta[45];int top=0;while(_)sta[++top]=_%10,_/=10;if(!top)putchar('0');while(top)putchar(sta[top]+'0'),--top;putchar('.');for(int i=0;i<set_precision;i++)x*=10;_=x;while(_)sta[++top]=_%10,_/=10;for(int i=0;i<set_precision-top;i++)putchar('0');while(top)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;}template<class _Tp>Writer&operator<<(vector<_Tp>vec){for(unsigned i=0;i<vec.size()-1;i++)cout<<vec[i]<<" ";cout<<vec[vec.size()-1];return *this;}template<class _Tp,class _tp>Writer&operator<<(pair<_Tp,_tp>a){cout<<a.first<<" "<<a.second;return *this;}Writer(){}}cout;}
#define cin Fastio :: cin
#define cout Fastio :: cout
#define endl Fastio :: endl

g++ a.cpp -o a -Wall -fsanitize=undefined,address

缺省源

#include<bits/stdc++.h>
// #define int long long
#define N (2)
#define I i
#define J j
#define raed read
#define reaD read
#define reAD read
#define rEAD read
#define READ read
#define REAd read
#define REad read
#define Read read
#define Reda read
#define redA read
#define reDA read
#define redA read
#define itn signed
#define Itn signed
#define ITN signed
#define Int signed
#define INT signed
#define foR for
#define fot for
#define foT for
#define sort stable_sort
using namespace std;
namespace IO
{
    #define ll signed
    const int MAX=1<<24;
    char buf[MAX],*p1=buf,*p2=buf;
    char obuf[MAX],*o=obuf;
    #define gc()(IO::p1==IO::p2&&(IO::p2=(IO::p1=IO::buf)+fread(IO::buf,1,1<<24,stdin),IO::p1==IO::p2)?EOF:*IO::p1++)
    //template<typename T>
    //inline T read()
    inline int read()
    {
        int x(0);bool f(true);
        char c(gc());
        for(;c<48||c>57;c=gc())if(c=='-')f=false;
        for(;c>=48&&c<=57;c=gc())x=(x<<3)+(x<<1)+(c^48);
        return f?x:~x+1;
    }
    inline double dead()
    {
        double x(0);bool f(true);
        int lee(0);char c(gc());
        for(;c<48||c>57;c=gc())if(c=='-')f=false;
        for(;c>=48&&c<=57;c=gc())x=x*10+(c^48);
        if(c=='.')
        {
            c=gc();
            for(;c>=48&&c<=57;c=gc())x=(x*10.0+(c^48)),++lee;
            x/=pow(10,lee);
        }
        return f?x:-x;
    }
    inline double sead()
    {
        double x(0);bool f(true);
        long long d(0);int lee(0);char c(gc());
        for(;c<48||c>57;c=gc())if(c=='-')f=false;
        for(;c>=48&&c<=57;c=gc())d=(d<<3)+(d<<1)+(c^48);
        if(c=='.')
        {
            c=gc();
            for(;c>=48&&c<=57;c=gc())d=(d<<3)+(d<<1)+(c^48),++lee;
            x=1.0*d/pow(10,lee);
        }
        else return d;
        return f?x:-x;
    }
    void print(ll x){if(x>9)print(x/10);*o++=(x%10)+'0';}
    void pit(ll x){if(x<0)*o++='-',x=~x+1;print(x);}
    void write(ll x,char ed){pit(x);*o++=ed;}
    void flush(){fwrite(obuf,o-obuf,1,stdout);}
    #undef ll
}
using IO::read;using IO::write;using IO::flush;using IO::dead;using IO::sead;
inline signed min(signed x,signed y){return y&((y-x)>>31)|x&(~(y-x)>>31);}
inline signed max(signed x,signed y){return x&((y-x)>>31)|y&(~(y-x)>>31);}
inline long long min(long long x,long long y){return y&((y-x)>>63)|x&(~(y-x)>>63);}
inline long long max(long long x,long long y){return x&((y-x)>>63)|y&(~(y-x)>>63);}
inline void swap(int &x,int &y){x^=y^=x^=y;}
int n,m,k;
void init_set()
{
    #ifndef ONLINE_JUDGE
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
    #endif
    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
}
signed main()
{
    init_set();
	
    flush();
    return 0;
}

文本比对

diff a.out out.txt -b