[20251122] BOJ / G5 / 감시 피하기 / 이준희

Author: JHLEE325

JHLEE325/202511/22 BOJ G5 감시 피하기.md

@@ -0,0 +1,81 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static int N;
+    static char[][] map;
+    static List<int[]> blank = new ArrayList<>();
+    static List<int[]> teacher = new ArrayList<>();
+    static boolean found = false; // 성공 여부
+
+    static int[] dr = {-1, 1, 0, 0};
+    static int[] dc = {0, 0, -1, 1};
+
+    public static void main(String[] args) throws Exception {
+
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        N = Integer.parseInt(br.readLine());
+
+        map = new char[N][N];
+
+        for (int i = 0; i < N; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < N; j++) {
+                map[i][j] = st.nextToken().charAt(0);
+
+                if (map[i][j] == 'X') blank.add(new int[]{i, j});
+                if (map[i][j] == 'T') teacher.add(new int[]{i, j});
+            }
+        }
+
+        dfs(0, 0);
+
+        System.out.println(found ? "YES" : "NO");
+    }
+
+    static void dfs(int idx, int cnt) {
+        if (found) return;
+
+        if (cnt == 3) {
+            if (check()) found = true;
+            return;
+        }
+
+        if (idx >= blank.size()) return;
+
+        int r = blank.get(idx)[0];
+        int c = blank.get(idx)[1];
+
+        map[r][c] = 'O';
+        dfs(idx + 1, cnt + 1);
+
+        map[r][c] = 'X';
+        dfs(idx + 1, cnt);
+    }
+
+    static boolean check() {
+        for (int[] t : teacher) {
+            int tr = t[0];
+            int tc = t[1];
+
+            for (int d = 0; d < 4; d++) {
+                int nr = tr;
+                int nc = tc;
+
+                while (true) {
+                    nr += dr[d];
+                    nc += dc[d];
+
+                    if (nr < 0 || nc < 0 || nr >= N || nc >= N) break;
+
+                    if (map[nr][nc] == 'O') break;
+                    if (map[nr][nc] == 'S') return false;
+                }
+            }
+        }
+        return true;
+    }
+}
+```