本题的目标很简单,就是判断一个给定的正整数是否素数。
输入格式:
输入在第一行给出一个正整数N(≤ 10),随后N行,每行给出一个小于2
31
的需要判断的正整数。
输出格式:
对每个需要判断的正整数,如果它是素数,则在一行中输出Yes,否则输出No。
输入样例:
2
11
111
输出样例:
Yes
No
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
//** Class for buffered reading int and double values *//*
class Reader {
static BufferedReader reader;
static StringTokenizer tokenizer;
// ** call this method to initialize reader for InputStream *//*
static void init(InputStream input) {
reader = new BufferedReader(new InputStreamReader(input));
tokenizer = new StringTokenizer("");
}
// ** get next word *//*
static String next() throws IOException {
while (!tokenizer.hasMoreTokens()) {
// TODO add check for eof if necessary
tokenizer = new StringTokenizer(reader.readLine());
}
return tokenizer.nextToken();
}
static boolean hasNext()throws IOException {
return tokenizer.hasMoreTokens();
}
static String nextLine() throws IOException{
return reader.readLine();
}
static char nextChar() throws IOException{
return next().charAt(0);
}
static int nextInt() throws IOException {
return Integer.parseInt(next());
}
static float nextFloat() throws IOException {
return Float.parseFloat(next());
}
}
public class Main {
public static void main(String[] args) throws IOException {
Reader.init(System.in);
int n = Reader.nextInt();
for (int i = 0; i < n; i++) {
int m = Reader.nextInt();
if (isPrime(m)) {
System.out.println("Yes");
}else {
System.out.println("No");
}
}
}
public static boolean isPrime(int num) {
if(num==2||num==3) {
return true;
}
if (num==1||num%6!=1&&num%6!=5) {
return false;
}
int temp = (int) Math.sqrt(num);
for (int i = 5; i < temp; i+=6) {
if (num%i==0||num%(i+2)==0) {
return false;
}
}
return true;
}
}