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;