[백준] 300 - 수학 1 : 최대공약수와 최소공배수 (2609번 JAVA)

[백준] 300 - 수학 1 : 최대공약수와 최소공배수 (2609번 JAVA)

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[GCD 사용전]

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.StringTokenizer;

public class Main{
    
    public static void main(String[] args) throws IOException{

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        StringTokenizer st = new StringTokenizer(br.readLine());

        int a = Integer.parseInt(st.nextToken());
        int b = Integer.parseInt(st.nextToken());

        int n1 = 0;
        long n2 = 0;

        for(int i=Math.min(a, b); i>0; i--){
            if (a%i == 0 && b%i == 0){
                n1 = i;
                break;
            }
        }
        bw.write(n1+"\n");

        for(long i=Math.max(a, b); i<=100000000; i+=n1){
            if (i%a == 0 && i%b == 0){
                n2 = i;
                break;
            }
        }
        bw.write(n2+"\n");

        bw.flush();
        bw.close();
    }
}

---

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.StringTokenizer;

public class Main{

    public static int a;
    public static int b;
    
    public static void main(String[] args) throws IOException{

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        StringTokenizer st = new StringTokenizer(br.readLine());

        a = Integer.parseInt(st.nextToken());
        b = Integer.parseInt(st.nextToken());

        bw.write(GND(a, b) + "\n");
        bw.write(LCM(a, b) + "\n");

        bw.flush();
        bw.close();
    }

    // Greatest Common Divisor (최대 공약수)
    public static int GND (int a, int b) {
        
        while(b != 0){
            int r = a % b;
            a = b;
            b = r;
        }

        return a;
    }

    // Least Common mulitple (최소 공배수)
    public static int LCM (int a, int b) {
        return a * b / GND(a, b);
    }
}

[참고 자료]

https://st-lab.tistory.com/154

[백준] 2609번 : 최대공약수와 최소공배수 - JAVA [자바]