ACM：读入优化

两个简单的读入优化

 int getin(){
     int ans=;char tmp;bool sign=;
     while(!isdigit(tmp=getchar()) && tmp!='-');
     if(tmp=='-')sign=,tmp=getchar();
     do ans=(ans<<)+(ans<<)+tmp-'';
     while(isdigit(tmp=getchar()));
     return  sign?-ans:ans;
 }

 inline int read(){
     int p,data=;
     char ch=;
     while ((ch!='-') && ch<'' || ch>'') ch=getchar();
     if (ch=='-')
     {
         p=-;
         ch=getchar();
     } else p=;
     while (ch>='' && ch<='') data=data*+ch-'',ch=getchar();
     return data*p;
 }

大佬的读入优化

from：https://blog.csdn.net/x_iya/article/details/9003416

 namespace fastIO{
     #define BUF_SIZE 100000
     #define OUT_SIZE 100000
     #define ll long long
     //fread->read
     bool IOerror=;
     inline char nc(){
         static char buf[BUF_SIZE],*p1=buf+BUF_SIZE,*pend=buf+BUF_SIZE;
         if (p1==pend){
             p1=buf; pend=buf+fread(buf,,BUF_SIZE,stdin);
             if (pend==p1){IOerror=;return -;}
             //{printf("IO error!\n");system("pause");for (;;);exit(0);}
         }
         return *p1++;
     }
     inline bool blank(char ch){return ch==' '||ch=='\n'||ch=='\r'||ch=='\t';}
     inline void read(int &x){
         bool sign=; char ch=nc(); x=;
         for (;blank(ch);ch=nc());
         if (IOerror)return;
         if (ch=='-')sign=,ch=nc();
         for (;ch>=''&&ch<='';ch=nc())x=x*+ch-'';
         if (sign)x=-x;
     }
     inline void read(ll &x){
         bool sign=; char ch=nc(); x=;
         for (;blank(ch);ch=nc());
         if (IOerror)return;
         if (ch=='-')sign=,ch=nc();
         for (;ch>=''&&ch<='';ch=nc())x=x*+ch-'';
         if (sign)x=-x;
     }
     inline void read(double &x){
         bool sign=; char ch=nc(); x=;
         for (;blank(ch);ch=nc());
         if (IOerror)return;
         if (ch=='-')sign=,ch=nc();
         for (;ch>=''&&ch<='';ch=nc())x=x*+ch-'';
         if (ch=='.'){
             double tmp=; ch=nc();
             for (;ch>=''&&ch<='';ch=nc())tmp/=10.0,x+=tmp*(ch-'');
         }
         if (sign)x=-x;
     }
     inline void read(char *s){
         char ch=nc();
         for (;blank(ch);ch=nc());
         if (IOerror)return;
         for (;!blank(ch)&&!IOerror;ch=nc())*s++=ch;
         *s=;
     }
     inline void read(char &c){
         for (c=nc();blank(c);c=nc());
         if (IOerror){c=-;return;}
     }
     //getchar->read
     inline void read1(int &x){
         char ch;int bo=;x=;
         for (ch=getchar();ch<''||ch>'';ch=getchar())if (ch=='-')bo=;
         for (;ch>=''&&ch<='';x=x*+ch-'',ch=getchar());
         if (bo)x=-x;
     }
     inline void read1(ll &x){
         char ch;int bo=;x=;
         for (ch=getchar();ch<''||ch>'';ch=getchar())if (ch=='-')bo=;
         for (;ch>=''&&ch<='';x=x*+ch-'',ch=getchar());
         if (bo)x=-x;
     }
     inline void read1(double &x){
         char ch;int bo=;x=;
         for (ch=getchar();ch<''||ch>'';ch=getchar())if (ch=='-')bo=;
         for (;ch>=''&&ch<='';x=x*+ch-'',ch=getchar());
         if (ch=='.'){
             double tmp=;
             for (ch=getchar();ch>=''&&ch<='';tmp/=10.0,x+=tmp*(ch-''),ch=getchar());
         }
         if (bo)x=-x;
     }
     inline void read1(char *s){
         char ch=getchar();
         for (;blank(ch);ch=getchar());
         for (;!blank(ch);ch=getchar())*s++=ch;
         *s=;
     }
     inline void read1(char &c){for (c=getchar();blank(c);c=getchar());}
     //scanf->read
     inline void read2(int &x){scanf("%d",&x);}
     inline void read2(ll &x){
         #ifdef _WIN32
             scanf("%I64d",&x);
         #else
         #ifdef __linux
             scanf("%lld",&x);
         #else
             puts("error:can't recognize the system!");
         #endif
         #endif
     }
     inline void read2(double &x){scanf("%lf",&x);}
     inline void read2(char *s){scanf("%s",s);}
     inline void read2(char &c){scanf(" %c",&c);}
     inline void readln2(char *s){gets(s);}
     //fwrite->write
     struct Ostream_fwrite{
         char *buf,*p1,*pend;
         Ostream_fwrite(){buf=new char[BUF_SIZE];p1=buf;pend=buf+BUF_SIZE;}
         void out(char ch){
             if (p1==pend){
                 fwrite(buf,,BUF_SIZE,stdout);p1=buf;
             }
             *p1++=ch;
         }
         void print(int x){
             static char s[],*s1;s1=s;
             if (!x)*s1++='';if (x<)out('-'),x=-x;
             while(x)*s1++=x%+'',x/=;
             while(s1--!=s)out(*s1);
         }
         void println(int x){
             static char s[],*s1;s1=s;
             if (!x)*s1++='';if (x<)out('-'),x=-x;
             while(x)*s1++=x%+'',x/=;
             while(s1--!=s)out(*s1); out('\n');
         }
         void print(ll x){
             static char s[],*s1;s1=s;
             if (!x)*s1++='';if (x<)out('-'),x=-x;
             while(x)*s1++=x%+'',x/=;
             while(s1--!=s)out(*s1);
         }
         void println(ll x){
             static char s[],*s1;s1=s;
             if (!x)*s1++='';if (x<)out('-'),x=-x;
             while(x)*s1++=x%+'',x/=;
             while(s1--!=s)out(*s1); out('\n');
         }
         void print(double x,int y){
             static ll mul[]={,,,,,,,,,
                 ,10000000000LL,100000000000LL,1000000000000LL,10000000000000LL,
                 100000000000000LL,1000000000000000LL,10000000000000000LL,100000000000000000LL};
             if (x<-1e-)out('-'),x=-x;x*=mul[y];
             ll x1=(ll)floor(x); if (x-floor(x)>=0.5)++x1;
             ll x2=x1/mul[y],x3=x1-x2*mul[y]; print(x2);
             if (y>){out('.'); for (size_t i=;i<y&&x3*mul[i]<mul[y];out(''),++i); print(x3);}
         }
         void println(double x,int y){print(x,y);out('\n');}
         void print(char *s){while (*s)out(*s++);}
         void println(char *s){while (*s)out(*s++);out('\n');}
         void flush(){if (p1!=buf){fwrite(buf,,p1-buf,stdout);p1=buf;}}
         ~Ostream_fwrite(){flush();}
     }Ostream;
     inline void print(int x){Ostream.print(x);}
     inline void println(int x){Ostream.println(x);}
     inline void print(char x){Ostream.out(x);}
     inline void println(char x){Ostream.out(x);Ostream.out('\n');}
     inline void print(ll x){Ostream.print(x);}
     inline void println(ll x){Ostream.println(x);}
     inline void print(double x,int y){Ostream.print(x,y);}
     inline void println(double x,int y){Ostream.println(x,y);}
     inline void print(char *s){Ostream.print(s);}
     inline void println(char *s){Ostream.println(s);}
     inline void println(){Ostream.out('\n');}
     inline void flush(){Ostream.flush();}
     //puts->write
     char Out[OUT_SIZE],*o=Out;
     inline void print1(int x){
         static char buf[];
         char *p1=buf;if (!x)*p1++='';if (x<)*o++='-',x=-x;
         while(x)*p1++=x%+'',x/=;
         while(p1--!=buf)*o++=*p1;
     }
     inline void println1(int x){print1(x);*o++='\n';}
     inline void print1(ll x){
         static char buf[];
         char *p1=buf;if (!x)*p1++='';if (x<)*o++='-',x=-x;
         while(x)*p1++=x%+'',x/=;
         while(p1--!=buf)*o++=*p1;
     }
     inline void println1(ll x){print1(x);*o++='\n';}
     inline void print1(char c){*o++=c;}
     inline void println1(char c){*o++=c;*o++='\n';}
     inline void print1(char *s){while (*s)*o++=*s++;}
     inline void println1(char *s){print1(s);*o++='\n';}
     inline void println1(){*o++='\n';}
     inline void flush1(){if (o!=Out){if (*(o-)=='\n')*--o=;puts(Out);}}
     struct puts_write{
         ~puts_write(){flush1();}
     }_puts;
     inline void print2(int x){printf("%d",x);}
     inline void println2(int x){printf("%d\n",x);}
     inline void print2(char x){printf("%c",x);}
     inline void println2(char x){printf("%c\n",x);}
     inline void print2(ll x){
         #ifdef _WIN32
             printf("%I64d",x);
         #else
         #ifdef __linux
             printf("%lld",x);
         #else
             puts("error:can't recognize the system!");
         #endif
         #endif
     }
     inline void println2(ll x){print2(x);printf("\n");}
     inline void println2(){printf("\n");}
     #undef ll
     #undef OUT_SIZE
     #undef BUF_SIZE
 };
 using namespace fastIO;