OJ Board

Code: Select all

#include<stdio.h>
#include<string.h>
#include<math.h>
#define N 10100
main()
{
	long k=0,i,j,l,z,a[N],r,m,n,val;
	for(i=2;i<=10100;i++)
	{
		for(j=2;j<=(i/2);j++)
			if(!(i%j))
				break;
		if(j>(i/2)) a[k++]=i;
	}
	while(1)
	{
		r=scanf("%ld%ld",&m,&n);
		if(r==EOF) break;
		z=0;
		for(i=m;i<=n;i++)
		{
			val=(i*i)+i+41;
			l=0;
			for(j=0;a[j]<=sqrt(val);j++)
				if(!(val%a[j]))
				{
					l=1;
					break;
				}
			if(!l) z++;
		}
		printf("%.2lf\n",z*100.00/(double)(n-m+1));
	}
	return 0;
} :oops:  :oops: 

Code: Select all

#include<stdio.h>
#include<string.h>
#include<math.h>
#define N 10100
main()
{
	long k=0,i,j,l,z,a[N],r,m,n,val;
	for(i=2;i<=10100;i++)
	{
		for(j=2;j<=(i/2);j++)
			if(!(i%j))
				break;
		if(j>(i/2)) a[k++]=i;
	}
	while(1)
	{
		r=scanf("%ld%ld",&m,&n);
		if(r==EOF) break;
		z=0;
		for(i=m;i<=n;i++)
		{
			val=(i*i)+i+41;
			l=0;
			for(j=0;a[j]<=sqrt(val);j++)
				if(!(val%a[j]))
				{
					l=1;
					break;
				}
			if(!l) z++;
		}
		printf("%.2lf\n",z*100.00/(double)(n-m+1));
	}
	return 0;
}

Code: Select all

#include<stdio.h>
#include<math.h>

#define size 500000

int prime[size];
int prime_no=2;

void init(){
	
	register long int i ;
	
	prime[0]=1;
	prime[1]=2;
	
	for(i =2;i<size;i++){
		prime[i]=0;

	}

}

void prime_gen(long int n ){

	register int flag;
	register long int i,j;
	flag=0;

	init();

	for(i=3;i<=n;i+=2){
		for(j=1;j<prime_no && !flag; j++){

			if((i%prime[j])==0){

				flag=1;
			}
			else
				continue;
		}

		if(flag==0){

			prime[prime_no++]=i;
		}

		flag=0;
	}
}




int check(long int c){
	register int low,high,mid;
	low=0;
	high=prime_no -1;
	while(low<=high){
	
		mid=(low+high)/2;

		if(c<prime[mid])
			high=mid-1;
		else if(c> prime[mid])
			low=mid+1;
		else
			return 1;
	
	
	
	}
	return 0;


}


void calculate( int e, int l){

	register int i,total;
	long int temp;
	int count=0;
	double result,t1,t2;
	int flag=0;
	total=l-e+1;
	

	for(i=e;i<=l;i++){
	
		temp=i*i + i + 41;
		flag=check(temp);
		if(flag==1){
		
			count++;
			
		}
		else
			continue;
		flag=0;
	
	}
	

	t1=count;
	t2=total;
	result=(t1/t2)*100;
	
	printf("result is %0.2lf\n",result);
	




}






int main(){

	int e,l;
	

	prime_gen(100010041);

	while(scanf("%d %d",&e,&l)==2){
		
		calculate(e,l);
		
	
	
	}
	
	return 0;
}

Code: Select all

#include<stdlib.h>
#include<malloc.h>

#define isprime(f,x) (*(f+(x)/16)&(1<<(((x)%16L)/2)))
#define setprime(f,x) *(f+(x)/16)|=1<<(((x)%16L)/2)

void main()
{
unsigned char *field=NULL,*zzz;
unsigned long teste=1,max,mom,count,alloc;
int d;
max=20010000L;

while(field==NULL)
zzz=field=(unsigned char*) malloc(alloc=(((max-=10000L)>>4)+1L));

for (count=0;count<alloc;count++)
*zzz++ = 0x00;

while((teste+=2)<max)
if(!isprime(field,teste))
for(mom=3L*teste;mom<max;mom+=teste<<1)
setprime(field,mom);
	if(isprime(field,3)==1)
/*now you can call the module isprime to check any positive integer 
either prime or not; 
syntax: 
isprime(field,integer); 

if the module return 0 the integer will be prime 
else not prime. 

you can check upto 20000000 within a while 
*/ 

free (field); 
}

/* ***********************************************/
MY QUESTION----->
/*what should i use in place of the parameter "field" in the function 
isPrime(field , integer). that means what should i do if i want to check the primality of the number 100010041.*/ 

/*********************************************/






/**********************SIEVE********************************/



#define MAXSIEVE 100000000 // All prime numbers up to this 
#define MAXSIEVEHALF (MAXSIEVE/2) 
#define MAXSQRT 5000 // sqrt(MAXSIEVE)/2 
char a[MAXSIEVE/16+2]; 
#define isprime(n) (a[(n)>>4]&(1<<(((n)>>1)&7))) // Works when n is odd 

int i,j; 
memset(a,255,sizeof(a)); 
a[0]=0xFE; 
for(i=1;i<MAXSQRT;i++) 
if (a[i>>3]&(1<<(i&7))) 
for(j=i+i+i+1;j<MAXSIEVEHALF;j+=i+i+1) 
a[j>>3]&=~(1<<(j&7)); 

Code: Select all

#include<stdio.h>

#include<math.h>


int isPrime(long int x){

	register long int i ;
	
	for(i=2;i<=sqrt(x);i++){
	
		if((x%i)==0){
			
			return 0;
		}
		else
			
			continue;
	}
	return 1;


}


void calculate(int a , int b){


	register  int i,check;
	long int temp;
	double count=0;
	double total;
	
	
	total=b-a+1;
	
	for(i=a;i<=b;i++){
	
		temp=i*i + i + 41;
		
			
		check=isPrime(temp);
		if(check==1){
			count++;
		}
		else
			continue;
		
	
	}
	count=(count/total)*100;
	printf("%.2lf\n",count);



}


int main(){

	int a,b;
	
	
	while(scanf("%d %d",&a,&b)==2){
	
		calculate(a,b);
	
	}
	
	
	return 0;
}