[20250821] BOJ / G4 / 별 찍기 - 18 / 김민진

zinnnn37/202508/21 BOJ G4 별 찍기 - 18.md

@@ -0,0 +1,88 @@
+```java
+import java.io.*;
+
+public class BJ_10933_별_찍기_18 {
+
+	private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+
+	private static int N;
+	private static int height;
+	private static int width;
+
+	private static char[][] mat;
+
+	public static void main(String[] args) throws IOException {
+		init();
+		sol();
+	}
+
+	private static void init() throws IOException {
+		N      = Integer.parseInt(br.readLine());
+		height = (int) (Math.pow(2, N) - 1);
+		width  = height * 2 - 1;
+
+		mat = new char[height][width];
+	}
+
+	private static void sol() throws IOException {
+		rec(N, 0, 0);
+		printMat();
+	}
+
+	private static void rec(int n, int x, int y) {
+		if (n == 1) {
+			mat[x][y] = '*';
+			return;
+		}
+
+		int h = (int) (Math.pow(2, n) - 1);
+		int w = h * 2 - 1;
+
+		if (n % 2 == 1) {
+			for (int i = 0; i <= w / 2; i++) {
+				mat[x + h - i - 1][y + i]             = '*';
+				mat[x + h - i - 1][y + h * 2 - i - 2] = '*';
+				mat[x + h - 1][y + i]                 = '*';
+				mat[x + h - 1][y + h * 2 - i - 2]     = '*';
+			}
+			rec(n - 1, x + h / 2, y + w / 4 + 1);
+		} else {
+			for (int i = 0; i <= w / 2; i++) {
+				mat[x][y + i]                 = '*';
+				mat[x][y + h * 2 - i - 2]     = '*';
+				mat[x + i][y + i]             = '*';
+				mat[x + i][y + h * 2 - i - 2] = '*';
+			}
+			rec(n - 1, x + 1, y + w / 4 + 1);
+		}
+	}
+
+	private static void printMat() throws IOException {
+		for (char[] chars : mat) {
+			// 각 줄에서 마지막 '*'의 위치 찾기
+			int lastStar = -1;
+			for (int i = chars.length - 1; i >= 0; i--) {
+				if (chars[i] == '*') {
+					lastStar = i;
+					break;
+				}
+			}
+
+			// 마지막 별까지만 출력
+			for (int i = 0; i <= lastStar; i++) {
+				if (chars[i] == '*') {
+					bw.write('*');
+				} else {
+					bw.write(' ');
+				}
+			}
+			bw.write("\n");
+		}
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+
+}
+```