Sieve of Eratosthenes March 21, 2010

SPOJ 2. Prime Generator.
Code works for smaller inputs

//sieve of Erastosthenes
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#include<iostream>
#include<algorithm>
#include<vector>
#include<math.h>
using namespace std;
vector<int> prime;

void sieve(int n)
{
  for(int i=0;i<=n;i++)
    prime.push_back(1);
 
  prime[0]=0;
  prime[1]=0;

  int m=sqrt(n);

  for(int i=2;i<=m;i++)
   if(prime[i])
     for(int k=i*i;k<=n;k=k+i)
       prime[k]=0;  

}
int main()
{
  
  sieve(1000);

  int cases;
  scanf("%d",&cases);
  while(cases--){
  int m,n;
  scanf("%d%d",&m,&n);
  for(int i=max(2,m);i<=n;i++){
   if(prime[i])
    printf("%d\n",i);
   }
  if(cases!=0)
  printf("\n");
  }

return 0;
}

TJU 3241. Fermat square prime January 10, 2010

TJU 3241. Fermat square prime
WA
TODO

#include<stdio.h>
#include<math.h>
int prime(int n)
{
  int i,j,flag;
  flag=1;
  j=sqrt(n);
  for(i=2;i<=j;i++)
  {
     if(n%i==0){
      flag=0;
      break;
     }
  }

  if(flag==1&&n!=1) return 1;
  else return 0;


}
int main()
{
 int i,j,k,rem;
 int cases;
 int n;
 
 scanf("%d",&cases);
 while(cases--)
 {
   scanf("%d",&n);

   if(prime(n)==1){
   rem=n%4;
   
   if(rem==1) printf("yes\n");
   else printf("no\n");
   }
   else
      printf("no\n");
 }

return 0;
}