how to take fast output using getchar_unlocked

general
,
1

can anyone explain the logic behind fast input and output…?
and why we use getchar_unlocked…??

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2

please help for java language …

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3

and c++ also… :slight_smile:

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In c or c++ :

here pf is for print and sf is for input

inline void pf(int a)

{

char snum[200];
int i=0;
do
{
	snum[i++]=a%10+48;
	a=a/10;
}while(a!=0);
i=i-1;
while(i>=0)
putchar(snum[i--]);
//putchar('\n');

}

int sf()

{

register int c = getcx();
int num = 0;

for(; c < '0' || c > '9'; c = getcx());

for(; c >= '0' && c <= '9'; c = getcx())
	num = (num << 3) + (num << 1) + c - 48;

return num;

}

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5

and for java…??

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6

i don’t know for java… :stuck_out_tongue:

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@himanshu_95 do you think it will work for negative numbers also…??

8

@emin3m…it will not!!!

9

This topic has been already discussed here(The method is very well explained here)!!

Please try and search for topics before you add a new question!!

Also as @emin3m points out…the code snippet provided by @himanshu_95 will not work in the case of negative numbers!!!

For integers you can use this for ip:

int scan_d()
{
	int ip=getchar_unlocked(),ret=0,flag=1;
	for(;ip<'0'||ip>'9';ip=getchar_unlocked())
		if(ip=='-')
		{
			flag=-1;
			ip=getchar_unlocked();
			break;
		}
	for(;ip>='0'&&ip<='9';ip=getchar_unlocked())
		ret=ret*10+ip-'0';
	return flag*ret;
}

and this for op:

void print_d(int n)
{
	if(n<0)
	{
		n=-n;
		putchar_unlocked('-');
	}
	int i=10;
	char output_buffer[10];
	do
	{
		output_buffer[--i]=(n%10)+'0';
		n/=10;
	}while(n);
	do
	{
		putchar_unlocked(output_buffer[i]);
	}while(++i<10);
}

Also for fast io in java you can go through some of the codes here: LINK!!

Hope this helps…:slight_smile:

10

For java fast I/O check this answer