leetcode-Count Primes

Description:

Count the number of prime numbers less than a non-negative number, n

 1 int countPrimes(int n) {
 2     int i,j;
 3     bool *primer = malloc(sizeof(bool)*n);
 4     for(i=0;i<n;i++)
 5     {
 6         primer[i]=true;
 7     }
 8     primer[0] = false;
 9     primer[1] = false;
10     int limit = sqrt(n);
11     
12     for(i = 2; i <=limit;i++)
13     {
14         for(j = i*i;j<n;j+=i)
15         {
16             primer[j]=false;
17         }
18     }
19     int result = 0;
20     for(i = 0;i<n;i++)
21     {
22         if(primer[i])
23           result++;
24     }
25     return result;
26     
27 }