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L1-028 判断素数

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 231 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:

tex
2
11
111
2
11
111

输出样例:

tex
Yes
No
Yes
No

Solution:

java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    static String isPrime(int n) {
        if (n < 2) return "No";
        for (long i = 2; i * i <= n; i++) {
            if (n % i == 0) return "No";
        }
        return "Yes";
    }

    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(in.readLine());
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < n; i++) {
            if (i > 0) sb.append("\n");
            sb.append(isPrime(Integer.parseInt(in.readLine())));
        }
        System.out.println(sb);
    }
}
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    static String isPrime(int n) {
        if (n < 2) return "No";
        for (long i = 2; i * i <= n; i++) {
            if (n % i == 0) return "No";
        }
        return "Yes";
    }

    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(in.readLine());
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < n; i++) {
            if (i > 0) sb.append("\n");
            sb.append(isPrime(Integer.parseInt(in.readLine())));
        }
        System.out.println(sb);
    }
}

Released under the MIT License.