2438 별 찍기 - 1

* Scanner, StringBuilder, STATIC FINAL 상수

import java.util.Scanner;

public class Main {
	public static final String LINER = "\n";
	public static void main(String[] args) {
    	Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		int num = sc.nextInt();
		sc.close();
		
		for(int i=1; i<=num; i++) {
			for(int j=0; j<i; j++) {
				sb.append("*");
			}
			sb.append(LINER);
		}
		System.out.print(sb.toString());
	}
}

 

* BufferedReader, StringBuilder, STATIC FINAL 상수

import java.io.*;

public class Main {
	public static final String LINER = "\n";
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		int num = Integer.parseInt(br.readLine());
		br.close();
		
		for(int i=1; i<=num; i++) {
			for(int j=0; j<i; j++) {
				sb.append("*");
			}
			sb.append(LINER);
		}
		System.out.print(sb.toString());
	}
}

 

* 로직면에서 가장 빨랐던 것 (이렇게 할 수도있구나)

import java.io.*;

public class Main {
	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb1 = new StringBuilder();
		StringBuilder sb2 = new StringBuilder();

		int n = Integer.parseInt(br.readLine());	
        
		for(int i = 0; i < n; i++){
			sb1.append("*");
			sb2.append(sb1+"\n");
		}
		System.out.println(sb2);
	}
}

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단일 값을 가져옴에도 Scanner보다 BufferedReader가 더 좋은 효율을 보여줬다.