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Copy pathCheckPrimeNumber.java
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36 lines (28 loc) · 834 Bytes
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package algo_lib;
public class CheckPrimeNumber {
public boolean sieveCheckPrimeNumber(int number) {
if (number <= 1) return false;
boolean[] sieve = new boolean[number+1];
for (int i = 2; i*i <= number; ++i) {
if (!sieve[i]) {
for (int j = i*i; j <= number; j += i) {
sieve[j] = true;
}
}
}
return !sieve[number];
}
public int sieveCountPrimeNumber(int number) {
int count = 0;
boolean[] sieve = new boolean[number+1];
for (int i = 2; i <= number; ++i) {
if (!sieve[i]) {
++count;
for (int j = i; j <= number; j += i) {
sieve[j] = true;
}
}
}
return count;
}
}