BOJ #17836: 공주님을 구해라!

Author: ISKU

BOJ/17836/Main.java

@@ -0,0 +1,77 @@
+/*
+ * Author: Minho Kim (ISKU)
+ * Date: December 6, 2019
+ * E-mail: minho.kim093@gmail.com
+ *
+ * https://github.com/ISKU/Algorithm
+ * https://www.acmicpc.net/problem/17836
+ */
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+public static final int[] dy = { -1, 1, 0, 0 };
+public static final int[] dx = { 0, 0, -1, 1 };
+public static final int MAX = 500000;
+
+private static int[][] map;
+private static int Y, X, T;
+
+public static void main(String[] args) throws Exception {
+BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+StringTokenizer st = new StringTokenizer(br.readLine());
+Y = Integer.parseInt(st.nextToken());
+X = Integer.parseInt(st.nextToken());
+T = Integer.parseInt(st.nextToken());
+
+int pcount = 0;
+map = new int[Y][X];
+for (int y = 0; y < Y; y++) {
+st = new StringTokenizer(br.readLine());
+for (int x = 0; x < X; x++) {
+map[y][x] = Integer.parseInt(st.nextToken());
+if (map[y][x] == 2)
+pcount = (Y - 1 - y) + (X - 1 - x);
+}
+}
+
+int first = bfs(1);
+int second = bfs(2);
+if (first == MAX && second == MAX || (first > T && second + pcount > T)) {
+System.out.println("Fail");
+System.exit(0);
+}
+System.out.println((first < second + pcount) ? first : second + pcount);
+}
+
+private static int bfs(int target) {
+Queue<int[]> q = new LinkedList<>();
+int[][] visited = new int[Y][X];
+
+q.add(new int[] { 0, 0 });
+while (!q.isEmpty()) {
+int[] p = q.poll();
+int py = p[0];
+int px = p[1];
+int count = visited[py][px];
+if (target == 1 && py == Y - 1 && px == X - 1)
+return count;
+if (target == 2 && map[py][px] == 2)
+return count;
+
+for (int i = 0; i < 4; i++) {
+int y = py + dy[i];
+int x = px + dx[i];
+if (y < 0 || y >= Y || x < 0 || x >= X || visited[y][x] > 0 || map[y][x] == 1)
+continue;
+
+visited[y][x] = count + 1;
+q.add(new int[] { y, x });
+}
+}
+
+return MAX;
+}
+}