매일 Algorithm

백준 1676번

import java.util.Scanner;

public class problem465 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        int num = in.nextInt();
        int result = 0;
        while (num >= 5) {
            result += num / 5;
            num /= 5;
        }

        System.out.println(result);

    }
}

백준 17087번

import java.util.Arrays;
import java.util.Scanner;

public class problem466 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int size = in.nextInt(); // 동생 수
        int stay = in.nextInt(); // 내 위치
        int[] arr = new int[size];
        for (int i = 0; i < size; i++) {
            int a = in.nextInt();
            arr[i] = Math.abs(a - stay); // 내위치와 동생의 위치 절대값
        }
        Arrays.sort(arr);
        // 2 4 8
        int first = arr[0];
        for (int i = 1; i < arr.length; i++) {
            first = gcd(first, arr[i]); // 최소 공배수 찾기
        }

        System.out.println(first);
    }

    static int gcd(int a, int b) {
        if (b == 0) return a;
        return gcd(b, a % b);
    }
}

백준 1373번

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

public class problem467 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader
                (new InputStreamReader(System.in));
        // 2진수 -> 10진수
        BigInteger integer = new BigInteger(br.readLine(), 2);

        // 10진수 -> 8진수
        System.out.println(integer.toString(8));

    }
}

백준 1212번

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

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader
                (new InputStreamReader(System.in));

        BigInteger integer = new BigInteger(br.readLine(), 8);

        System.out.println(integer.toString(2));

    }
}