[20250312] BOJ / G1 / 구슬 탈출 2 / 김수연

suyeun84/202503/12 BOJ G1 구슬 탈출 2.md

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+```java
+import java.io.*;
+import java.util.*;
+
+public class boj13460 {
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static StringTokenizer st;
+    static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+    static int nextInt() {return Integer.parseInt(st.nextToken());}
+
+    static char[][] board;
+    static int N, M, answer = 11;
+    static Pos R, B, T;
+
+	public static void main(String[] args) throws Exception {
+		nextLine();
+		N = nextInt();
+		M = nextInt();
+		board = new char[N][M];
+
+		for (int i = 0; i < N; i++) {
+			String line = br.readLine();
+			for (int j = 0; j < M; j++) {
+				board[i][j] = line.charAt(j);
+				if (board[i][j] == 'R') R = new Pos(i, j, 'I');
+				else if (board[i][j] == 'B') B = new Pos(i, j, 'I');
+				else if (board[i][j] == 'O') T = new Pos(i, j, 'I');
+			}
+		}
+		move(R, B, 0);
+		if (answer == 11) System.out.println(-1);
+		else System.out.println(answer);
+	}
+
+	static void move(Pos cR, Pos cB, int cnt) {
+		if (cnt >= 10) return;
+		int[][] dir;
+		if (cR.m == 'V') {
+			dir = new int[][] {{0,-1}, {0,1}};
+		} else if (cR.m == 'H') {
+			dir = new int[][] {{-1, 0}, {1,0}};
+		} else {
+			dir = new int[][] {{-1, 0}, {1,0}, {0,-1}, {0,1}};
+		}
+		for (int[] d : dir) {
+			Pos nR = new Pos(cR.y, cR.x, cR.m);
+			Pos nB = new Pos(cB.y, cB.x, cB.m);
+			boolean RFlag = false, BFlag = false;
+			while (checkRange(nR.y+d[0], nR.x+d[1])) {
+				if (nR.y+d[0] == nB.y && nR.x+d[1] == nB.x) break;
+				nR.y += d[0];
+				nR.x += d[1];
+				if (nR.y == T.y && nR.x == T.x) {
+					RFlag = true;
+					nR.y = -1;
+					nR.x = -1;
+					break;
+				}
+			}
+			while (checkRange(nB.y+d[0], nB.x+d[1])) {
+				if (nB.y+d[0] == nR.y && nB.x+d[1] == nR.x) break;
+				nB.y += d[0];
+				nB.x += d[1];
+				if (nB.y == T.y && nB.x == T.x) {
+					BFlag = true;
+					nB.y = -1;
+					nB.x = -1;
+					break;
+				}
+			}
+			while (checkRange(nR.y+d[0], nR.x+d[1])) {
+				if (nR.y+d[0] == nB.y && nR.x+d[1] == nB.x) break;
+				nR.y += d[0];
+				nR.x += d[1];
+				if (nR.y == T.y && nR.x == T.x) {
+					RFlag = true;
+					break;
+				}
+			}
+			if (cR.y == nR.y && cR.x == nR.x && cB.y == nB.y && cB.x == nB.x) continue;
+			if (nR.m == 'H') {
+				nR.m = 'V';
+				nB.m = 'V';
+			} else if (nR.m == 'V') {
+				nR.m = 'H';
+				nB.m = 'H';
+			}
+			if ((RFlag && BFlag) || (!RFlag && BFlag)) continue;
+			else if (RFlag && !BFlag) {
+				answer = Math.min(answer, cnt+1);
+				return;
+			}
+
+			move(nR, nB, cnt+1);
+		}
+	}
+
+	static boolean checkRange(int y, int x) {
+		if (y > 0 && y < N-1 && x > 0 && x < M-1 && board[y][x] != '#') return true;
+		return false;
+	}
+
+	static class Pos {
+		int y, x;
+		char m;
+		public Pos(int y, int x, char m) {
+			this.y = y;
+			this.x = x;
+			this.m = m;
+		}
+	}
+}
+
+```