자바 트리 알고리즘(for문 다루기)

트리 1

 Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        for(int i=0 ; i<n ; i++){
            for(int j=0 ; j<=i ; j++){
                System.out.print("*");
            }
            System.out.println();
        }

트리 2

 Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        for(int i=n ; i>0 ; i--){
            for(int j=0 ; j<i ; j++){
                System.out.print("*");
            }
            System.out.println();
        }

트리 3

   Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        for(int i=0 ; i<n ; i++){
            for(int j=0 ; j<i ; j++){
                System.out.print(" ");
            }
            for(int j=5 ; j>i ; j--){
                System.out.print("*");
            }
            System.out.println();
        }

트리 4

 Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        for(int i=0 ; i<n ; i++){
            for(int j=n ; j>i ; j--){
                System.out.print(" ");
            }
            for(int j=0 ; j<i ; j++){
                System.out.print("*");
            }

            System.out.println();
        }

다른 풀이

  Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        for (int i = 0; i < n; i++) {

            for (int j = 0; j < n-(i+1); j++) {
                System.out.print(" ");
            }
            for (int k = n-(i+1); k < n; k++) {
                System.out.print("*");
            }

            System.out.println();
        }

트리 5 (한번 더 풀어봐야 됨)

for(int i=0;i<4;i++){
	for(int j=0;j<3-i;j++){
		System.out.print(" "); 
	}
	for(int j=0;j<2*i+1;j++){
		System.out.print("*"); 
	}
	System.out.println("");
}