[백준] 15552번 : 빠른 A+B - JAVA(자바)

https://www.acmicpc.net/problem/15552

15552번: 빠른 A+B

---

오답 코드 예시 (시간초과)

System.out.println() 을 각 테스트 케이스마다 해주면 당연히 시간초과가 나버리게 된다..! ㅠ,ㅠ

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

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());

        for(int i=0; i<T; i++){
            StringTokenizer st = new StringTokenizer(br.readLine(), " ");
            
            int A = Integer.parseInt(st.nextToken());
            int B = Integer.parseInt(st.nextToken());
            System.out.println(A + B); //시간초과
        }
    }
}

 

방법 1. BufferedWriter 사용

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.IOException;
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));

        int T = Integer.parseInt(br.readLine());

        for(int i=0; i<T; i++){
            StringTokenizer st = new StringTokenizer(br.readLine(), " ");
            bw.write(Integer.parseInt(st.nextToken()) + Integer.parseInt(st.nextToken()) + "\n");
        }
        br.close();
        bw.flush(); //버퍼 비우기
        bw.close(); //버퍼 닫기
    }
}

 

방법 2. StringBuilder 사용

테스트 케이스가 많아질 경우 StringBuilder를 사용하는 것이 앞서 말한 방식보다 빠를 수 있다.

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

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();

        for(int i=0; i<T; i++){
            StringTokenizer st = new StringTokenizer(br.readLine(), " ");
            sb.append(Integer.parseInt(st.nextToken()) + Integer.parseInt(st.nextToken())).append('\n');
        }
        br.close();
        System.out.println(sb);
    }
}