BOJ2178_미로탐색하기 java solution

mong3125/BFS/BOJ2178_미로탐색하기.java

@@ -0,0 +1,86 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.LinkedList;
+import java.util.Queue;
+import java.util.StringTokenizer;
+
+public class BOJ2178_미로탐색하기 {
+
+    static int n;
+    static int m;
+
+    static boolean[][] field;
+    static boolean[][] visited;
+    public static void main(String[] args) throws IOException {
+        // 입력
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        n = Integer.parseInt(st.nextToken());   // 세로 크기
+        m = Integer.parseInt(st.nextToken());   // 가로 크기
+
+        // 미로 선언
+        field = new boolean[n][m];
+        visited = new boolean[n][m];
+
+        // 미로 입력
+        for (int i = 0; i < n; i++) {
+            String line = br.readLine();
+            for (int j = 0; j < m; j++) {
+                field[i][j] = line.charAt(j) == '1';
+            }
+        }
+
+        // 문제 해결
+        int answer = bfs(0, 0);
+
+        // 출력
+        System.out.println(answer);
+    }
+
+    public static int bfs(int i, int j) {
+        Queue<int[]> queue = new LinkedList<>();
+        queue.add(new int[]{i, j, 1});
+        visited[i][j] = true;
+
+        while (!queue.isEmpty()) {
+            int[] now = queue.poll();
+
+            if (now[0] == n - 1 && now[1] == m - 1) {
+                return now[2];
+            }
+
+            if (isInRange(now[0] - 1, now[1])) {
+                if (!visited[now[0] - 1][now[1]] && field[now[0] - 1][now[1]]) {
+                    queue.add(new int[]{now[0] - 1, now[1], now[2] + 1});
+                    visited[now[0] - 1][now[1]] = true;
+                }
+            }
+            if (isInRange(now[0], now[1] - 1)) {
+                if (!visited[now[0]][now[1] - 1] && field[now[0]][now[1] - 1]) {
+                    queue.add(new int[]{now[0], now[1] - 1, now[2] + 1});
+                    visited[now[0]][now[1] - 1] = true;
+                }
+            }
+            if (isInRange(now[0] + 1, now[1])) {
+                if (!visited[now[0] + 1][now[1]] && field[now[0] + 1][now[1]]) {
+                    queue.add(new int[]{now[0] + 1, now[1], now[2] + 1});
+                    visited[now[0] + 1][now[1]] = true;
+                }
+            }
+            if (isInRange(now[0], now[1] + 1)) {
+                if (!visited[now[0]][now[1] + 1] && field[now[0]][now[1] + 1]) {
+                    queue.add(new int[]{now[0], now[1] + 1, now[2] + 1});
+                    visited[now[0]][now[1] + 1] = true;
+                }
+            }
+        }
+
+        return 0;
+    }
+
+    public static boolean isInRange(int i, int j) {
+        return 0 <= i && i < n && 0 <= j && j < m;
+    }
+}