关闭同步、解除绑定
ios::sync_with_stdio(false);注意：在使用后进行io操作时不能同时使用cin 与scanf。
另外可以进一步加快执行效率。
ios::sync_with_stdio(false);
cin.tie(0);读入整数
int read()
{
int x = 0, w = 1;
char ch = 0;
while(ch < '0' || ch > '9')
{
if(ch == '-')
w = -1;
ch = getchar();
}
while(ch >= '0' && ch <= '9')
{
x = x * 10 + ch - '0';
ch = getchar();
}
return x * w;
}输出整数
int write(int x)
{
if(x < 0)
{
x = -x;
putchar('-');
}
if(x > 9)
write(x / 10);
putchar(x % 10 + '0');
}非递归版输出
inline void write1(int x)
{
static int sta[35];
int top = 0;
do
{
sta[top++] = x % 10;
x /= 10;
}while(x);
while(top)
putchar(sta[--top] + '0');
}输入实数
inline double dbread()
{
double X = 0,Y = 1.0;
int w = 0;
char ch = 0;
while(!isdigit(ch))
{
w |= ch == '-';
ch = getchar();
}
while(isdigit(ch))
{
X = X * 10 + (ch^48);
ch = getchar();
}
ch = getchar();//读入小数点
while(isdigit(ch))
{
X += (Y /= 10) * (ch^48);
ch = getchar();
}
return w ? -X : X;
}自定义模板类
不适用于字符
template <typename T> inline T read(){ //声明 template 类,要求提供输入的类型T,并以此类型定义内联函数 read()
T sum=0,fl=1;//将 sum,fl 和 ch 以输入的类型定义
int ch=getchar();
for(;!isdigit(ch);ch=getchar()) if(ch=='-') fl=-1;
for(;isdigit(ch);ch=getchar()) sum=sum*10+ch-'0';
return sum*fl;
}如果要分别输入 int 类型的变量 a ， long long 类型的变量 b 和 _int128 类型的变量 c ，那么可以写成
a=read<int>();
b=read<long long>();
c=read<__int128>();示例：
template <typename T> inline int read()
{
int sum = 0,fl = 1;
int ch = getchar();
for(; !isdigit(ch); ch = getchar()) if(ch == '-') fl = -1;
for(; isdigit(ch); ch = getchar()) sum = sum * 10 + ch - '0';
return sum * fl;
}模板
另外附一份比较全的模板
//fread高速读入 如果用则全部都要用read不能再scanf或cin 测试需要重定向从文件输入数据（只能使用文件读入）
namespace fastIO {
#define BUF_SIZE 100000
#define OUT_SIZE 100000
#define ll long long
//fread->read
//快速读入
bool IOerror = 0;
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, 1, BUF_SIZE, stdin);
if (pend == p1) { IOerror = 1; return -1; }
//{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 = 0; char ch = nc(); x = 0;
for (; blank(ch); ch = nc());
if (IOerror)return;
if (ch == '-')sign = 1, ch = nc();
for (; ch >= '0'&&ch <= '9'; ch = nc())x = x * 10 + ch - '0';
if (sign)x = -x;
}
inline void read(ll &x) {
bool sign = 0; char ch = nc(); x = 0;
for (; blank(ch); ch = nc());
if (IOerror)return;
if (ch == '-')sign = 1, ch = nc();
for (; ch >= '0'&&ch <= '9'; ch = nc())x = x * 10 + ch - '0';
if (sign)x = -x;
}
inline void read(double &x) {
bool sign = 0; char ch = nc(); x = 0;
for (; blank(ch); ch = nc());
if (IOerror)return;
if (ch == '-')sign = 1, ch = nc();
for (; ch >= '0'&&ch <= '9'; ch = nc())x = x * 10 + ch - '0';
if (ch == '.') {
double tmp = 1; ch = nc();
for (; ch >= '0'&&ch <= '9'; ch = nc())tmp /= 10.0, x += tmp * (ch - '0');
}
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 = 0;
}
inline void read(char &c) {
for (c = nc(); blank(c); c = nc());
if (IOerror) { c = -1; return; }
}
//fwrite->write
//快速写入
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, 1, BUF_SIZE, stdout); p1 = buf;
}
*p1++ = ch;
}
void print(int x) {
static char s[15], *s1; s1 = s;
if (!x)*s1++ = '0'; if (x < 0)out('-'), x = -x;
while (x)*s1++ = x % 10 + '0', x /= 10;
while (s1-- != s)out(*s1);
}
void println(int x) {
static char s[15], *s1; s1 = s;
if (!x)*s1++ = '0'; if (x < 0)out('-'), x = -x;
while (x)*s1++ = x % 10 + '0', x /= 10;
while (s1-- != s)out(*s1); out('\n');
}
void print(ll x) {
static char s[25], *s1; s1 = s;
if (!x)*s1++ = '0'; if (x < 0)out('-'), x = -x;
while (x)*s1++ = x % 10 + '0', x /= 10;
while (s1-- != s)out(*s1);
}
void println(ll x) {
static char s[25], *s1; s1 = s;
if (!x)*s1++ = '0'; if (x < 0)out('-'), x = -x;
while (x)*s1++ = x % 10 + '0', x /= 10;
while (s1-- != s)out(*s1); out('\n');
}
void print(double x, int y) {
static ll mul[] = { 1,10,100,1000,10000,100000,1000000,10000000,100000000,
1000000000,10000000000LL,100000000000LL,1000000000000LL,10000000000000LL,
100000000000000LL,1000000000000000LL,10000000000000000LL,100000000000000000LL };
if (x < -1e-12)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 > 0) { out('.'); for (size_t i = 1; i < y&&x3*mul[i] < mul[y]; out('0'), ++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, 1, 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); } //y为小数点后几位
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(); } //清空
#undef ll
#undef OUT_SIZE
#undef BUF_SIZE
};
using namespace fastIO;