[백준] 15552번 빠른 A+B (BufferedReader,BufferedWriter) (Java)

15552번 빠른 A+B

기존에 쓰던 Scanner 를 쓰면 너무 느려서 탈락

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.IOException;
import java.util.StringTokenizer;
public class Main{
    public static void main(String args[]){
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        
        StringTokenizer st;
        
        for(int i=0; i<n; i++){
            st = new StringTokenizer(br.readLine(), " ");
            int a = Integer.parseInt(st.nextToken());
            int b = Integer.parseInt(st.nextToken());
            System.out.println(a+b);
            
        }
        
        
    }
}

했더니 exception을 잡아줘야함.

import java.io.BufferedReader;
import java.io.BufferedWriter;
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 n = Integer.parseInt(br.readLine());
        
        StringTokenizer st;
        
        for(int i=0; i<n; i++){
            st = new StringTokenizer(br.readLine(), " ");
            int a = Integer.parseInt(st.nextToken());
            int b = Integer.parseInt(st.nextToken());
            System.out.println(a+b);
            
        }
        
        
    }
}

를 쓰면 Scanner를 쓰지 않아도 System.out.println 때문에 시간초과가 뜬다.

버퍼에 담아둬았다가 한 번에 데이터를 보내는 BufferedWriter 를 써본다.

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 n = Integer.parseInt(br.readLine());
        
        StringTokenizer st;
        
        for(int i=0; i<n; i++){
            st = new StringTokenizer(br.readLine(), " ");
            bw.write((Integer.parseInt(st.nextToken()) + Integer.parseInt(st.nextToken())) + "\n");
            //int a = Integer.parseInt(st.nextToken());
            //int b = Integer.parseInt(st.nextToken());
            //System.out.println(a+b);
            
        }
        bw.flush();
        
        
        
    }
}

채점은 맞았다고 뜬다.

검색해보니 buffer는 flush 한 다음 cloase 해줘야한다고 한다. 그래서 br 과 bw를 닫아준다.

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