LeetCode - Count Primes

public class Solution {
    public int countPrimes(int n) {
    if(n <= 2)
    return 0;
    int count = 0;
    boolean[] prime = new boolean[n+1];
    for(int i=1; i<n+1; i++) {
        if(i % 2 == 0) {
            prime[i] = false;
        }
        else {
            prime[i] = true;
        }
    }
    for(int i=3; i<=Math.sqrt(n); i++) {
        if(prime[i]) {
            for(int j=2*i; j<n; j+=i) {
                prime[j] = false;
            }
        }
    }
    for(int i=1; i<n; i++) {
        if(prime[i]) {
            count++;
        }
    }
    return count;
    
    }
}