Quick Find primes

Quick Find primes

time limit: + ms | Memory Limit: 65535 KB

Difficulty: 3

Describe

now give you a positive integer N , you need to quickly find out the 2.....N These numbers contain all the primes.

Input

give a positive integer number N (n<=2000000)
but N to be 0 when the program ends.
The test data does not exceed - Group

Output

will be 2~n the output of all primes in the range. Two numbers separated by a space

Sample input

5

10

11

0

Sample output

2 3 5

2 3 5 7

2 3 5) 7 11

Code:

#include <stdio.h>int a[2000001]={0};int Main () {    int i,j,n;    for (i=2;i<=2000000;i++)    {        if (a[i]==0) for          (j=i+i;j<=2000000;j+=i)         a[j]=1;      }    while (scanf ("%d", &n)!=eof) {if (n==0) break;else{           printf ("2");           for (i=3;i<=n;i++)           if (a[i]==0)           printf ("%d", I);           printf ("\ n");}    }    return 0;}        

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Quick Find primes