Code: Select all
public static boolean[] getPrimes(int max) {
boolean[] result = new boolean[max + 1];
for(int i = 2; i < result.length; i++)
result[i] = true;
final double LIMIT = Math.sqrt(max);
for(int i = 2; i <= LIMIT; i++) {
if(result[i]) {
// cross out all multiples;
int index = 2 * i;
while(index < result.length){
result[index] = false;
index += i;
}
}
} return result;
}