ACM 10394 - Twin Primes

#include <stdio.h>

int isPrime[18409300] = {0};
int prime[100001][2] = {0};
int index = 0;
void creat()
{
    int i, j;
    for (i = 3; i < 18409300; i += 2)
    {
        if(!isPrime[i])
        {
            for (j = i + i; j < 18409300; j += i)
                isPrime[j] = 1;
            if (!isPrime[i - 2])
                prime[index][0] = i - 2, prime[index ++][1] = i;
        }
    } 
} 

int main()
{
    creat();
    int n;
    while (scanf("%d", &n) == 1)
        printf("(%d, %d)\n", prime[n][0], prime[n][1]);
    return 0;
}

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