[20251005] BOJ / P5 / 숨바꼭질 5 / 한종욱

Ukj0ng/202510/05 BOJ P5 숨바꼭질 5.md

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+```
+import java.io.*;
+import java.util.ArrayDeque;
+import java.util.Queue;
+import java.util.StringTokenizer;
+
+public class Main {
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static final int[] dx = {1, -1, 2};
+    private static boolean[][] visited;
+    private static int N, K;
+
+    public static void main(String[] args) throws IOException {
+        init();
+
+        int answer = BFS();
+
+        bw.write(answer + "\n");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void init() throws IOException {
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        K = Integer.parseInt(st.nextToken());
+
+        visited = new boolean[500001][2];
+    }
+
+    private static int BFS() {
+        Queue<int[]> q = new ArrayDeque<>();
+        int result = -1;
+        visited[N][0] = true;
+        q.add(new int[] {N, K, 0});
+
+        while (!q.isEmpty()) {
+            int[] current = q.poll();
+
+            if (visited[current[1]][current[2]%2]) {
+                result = current[2];
+                break;
+            }
+            int nt = current[2] + 1;
+            int nk = current[1] + nt;
+            if (OOB(nk)) continue;
+
+            for (int i = 0; i < 3; i++) {
+                int nx = current[0];
+
+                if (i == 2) nx *= dx[i];
+                else nx += dx[i];
+
+                if (OOB(nx) || visited[nx][nt%2]) continue;
+                visited[nx][nt%2] = true;
+                q.add(new int[]{nx, nk, nt});
+            }
+        }
+
+        return result;
+    }
+
+    private static boolean OOB(int nx) {
+        return nx < 0 || nx > 500000;
+    }
+}
+```