[백준] 11021번 : A + B - 7 - Java

https://www.acmicpc.net/problem/11021

11021번: A+B - 7

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구현 방법

입력

• Scanner
• BufferedReader + StringTokenizer
  * 자료형 타입 주의!
  * st.nextToken(): 문자열 반환 ➡ Integer.parseInt()로 int형으로 변환시켜야 함

출력

• System.out.println()
• BufferedWriter
  * BufferedWriter.write(): 단독으로 int형 값만 넣으면 아스키 코드값으로 인식되기에 다른 문자가 출력됨
  ➡ 반드시 문자열과 int형을 함께 넣어야 int값 제대로 출력
• StringBuilder

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풀이

1. Scanner + System.out.println()

import java.util.Scanner;

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

        Scanner in = new Scanner(System.in);
        int T = in.nextInt();

        for (int i = 1; i <= T; i++) {
            int A = in.nextInt();
            int B = in.nextInt();
 
            System.out.println("Case #" + i + ": " + (A + B));
        }
        in.close();
    }
}

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2. BufferedReader + StringTokenizer + System.out.println()

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.io.IOException;
 
public class Main {
    public static void main(String args[]) throws IOException {

        BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
        int T = Integer.parseInt(br.readLine());
        StringTokenizer st;
        
        for (int i = 1; i <= T; i++) {
            st = new StringTokenizer(br.readLine(), " ");
            
            System.out.println("Case #" + i + ": " 
                + (Integer.parseInt(st.nextToken())
                + Integer.parseInt(st.nextToken())));
        }
        br.close();
    }
}

 

3. BufferedReader + StringTokenizer + BufferedWriter

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
 
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));
		
        int T = Integer.parseInt(br.readLine());
        StringTokenizer st;
        
        for (int i = 1; i <= T; i++) {
            st = new StringTokenizer(br.readLine()," ");
            
            bw.write("Case #" + i + ": ");
            bw.write(Integer.parseInt(st.nextToken())
                + Integer.parseInt(st.nextToken()) + "\n");
        }
        br.close();
        bw.flush();
        bw.close();
    }
}

 

4. BufferedReader + StringTokenizer + StringBuilder

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.io.IOException;
 
public class Main {
    public static void main(String args[]) throws IOException {

        BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
        int T = Integer.parseInt(br.readLine());

        StringBuilder sb = new StringBuilder();
        StringTokenizer st;
        
        for (int i = 1; i <= T; i++) {
            st = new StringTokenizer(br.readLine(), " ");
            
            sb.append("Case #").append(i).append(": ")
                .append(Integer.parseInt(st.nextToken())
                + Integer.parseInt(st.nextToken())).append("\n");
        }
        br.close();
        System.out.println(sb);
    }
}

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성능

• BufferedReader > Scanner
• BufferedWriter / StringBuilder > System.out.println()

 

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출처 : https://st-lab.tistory.com/33