[java] 백준 단계별로 풀어보기 3단계 (2)

4단계 15552번 빠른 A + B

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

class Main{
    public static void main(String []args) throws IOException{
    	// 많은 양의 데이터를 입력받을 경우 Scanner보다 BufferedReader를 지향
        // Scanner는 space bar, Enter를 경계로 인식, BufferedReader는 Enter만 경계로 인식
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        
        // 자바에서 String을 token단위로 끊어주는 StringTokenizer클래스 제공
       	// 예를 들어 "hello java 8"이라는 문자열을 hello, java, 8 3개의 문자열로 끊어주는 기능 제공
        StringTokenizer st;
        int c = Integer.parseInt(br.readLine());
        for(int i=0; i<c; i++) {
            st = new StringTokenizer(br.readLine());
            bw.write((Integer.parseInt(st.nextToken()) + Integer.parseInt(st.nextToken())) +"\n");
        }
        bw.close();
    }
}

 

5단계 2741번 N 찍기

import java.util.Scanner;

class Main {
    public static void main(String []args) {
        
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        
        for(int i=0; i<n; i++){
            System.out.println(i+1);
        }
    }
}

 

6단계 2742번 기찍 N

import java.util.Scanner;

class Main {
    public static void main(String[] args) {
      
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        
        for(int i=n; i>0; i--){
            System.out.println(i);
        }
    }
}

 

7단계 11021번 제문 는하력출 지까N 터부1

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

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;
        int c = Integer.parseInt(br.readLine());
        for(int i=1; i<=c; i++){
            st = new StringTokenizer(br.readLine());
            bw.write("Case #" + i + ": " + 
                     (Integer.parseInt(st.nextToken()) + Integer.parseInt(st.nextToken())) + "\n");
        }
        bw.close();
    }
}

 

8단계 11022번  A + B를 조금 더 아름답게 출력하는 문제

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

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));
        
        int c = Integer.parseInt(br.readLine());
        StringTokenizer st;
        int a, b;
        for(int i=1; i<=c; i++){
            st = new StringTokenizer(br.readLine());
            a = Integer.parseInt(st.nextToken());
            b = Integer.parseInt(st.nextToken());
            bw.write("Case #" + i + ": " + a + " + " + b + 
                     " = " + (a + b) + "\n");
        }
        bw.close();
    }
}