TLE with Java code

[armanlalani5]

I am solving TDKPRIME - Finding the Kth Prime
I am using Sieve of Eratosthenes to answer the K queries. The length of the sieve array is 86028122 which is just enough to store the 5000000th prime number which is 86028121.
I am getting TLE error. Below is my code. Please suggest to me how can I optimize it further.

class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int t = sc.nextInt();

    int SIEVE_LEN = 86028122;
    int PRIMES_LEN = 5000000;

    boolean[] sieve = new boolean[SIEVE_LEN];
    int[] primes = new int[PRIMES_LEN];
    int count = 0;

    sieve[0] = true; sieve[1] = true;

    // if prime -> sieve[i] = false, else -> sieve[i] = true
    for(int i = 2; i < SIEVE_LEN; i++) {
        if(sieve[i] == false) {
            primes[count] = i;
            count++;
            for(int j = 2*i; j < SIEVE_LEN; j+=i) {
                sieve[j] = true;
            }
        }
    }

    while(t-- > 0) {
        int n = sc.nextInt();
        System.out.println(primes[n-1]);
    }
}

}

[simes]

Testing on IDEONE shows that the code takes around 1.7s to run. You can make it a little bit quicker by changing

for(int j = 2*i; j < SIEVE_LEN; j+=i)

to

for(int j = i*i; j < SIEVE_LEN; j+=i)

but then you’ll also need to prevent overflows of the i*i. On IDEONE, this got the time down to 1.2s, so that might just be enough. Failing that, you’ll need to use a smarter sieve. Or a different language.