배수빈: [CT] 자율주행 자동차_240909

CodeTree/2017-2018년/SB_자율주행_자동차.java

@@ -0,0 +1,109 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.StringTokenizer;
+
+public class SB_자율주행_자동차 {
+    static int N,M;
+    static int[][] board;
+    static boolean[][] visited;
+    static int[] dx = {-1, 0, 1, 0};    // 북동남서
+    static int[] dy = {0, 1, 0, -1};
+
+    static Car car;
+
+    private static boolean moveCar() {
+        for (int i = 0; i < 4; i++) {
+            int nd = (car.d + 3 - i) % 4;
+            int nx = car.x + dx[nd];
+            int ny = car.y + dy[nd];
+            if (!(0<=nx && nx<N && 0<=ny && ny<M) || visited[nx][ny]) continue;
+
+            if (board[nx][ny]==0 && !visited[nx][ny]) {
+                car.moveGo(nx, ny, nd);
+                visited[nx][ny] = true;
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static boolean backCar() {
+        int bd = (car.d + 2) % 4;
+        int bx = car.x + dx[bd];
+        int by = car.y + dy[bd];
+        if (!(0<=bx && bx<N && 0<=by && by<M)|| board[bx][by] == 1) return false;
+        car.moveBack(bx, by, car.d);
+        return true;
+    }
+
+    private static void play() {
+        visited[car.x][car.y] = true;           // 시작 위치 방문 처리
+        boolean canGo = moveCar();
+
+        // 좌회전해서 움직일 수 있을때까지 이동
+        while (canGo) {
+            canGo = moveCar();
+
+            // 더이상 못가면 후진
+            if (!canGo) {
+                if (backCar()) canGo = true;    // 후진가능하면, 후진 후 다시 이동
+                else break;
+            }
+        }
+        System.out.println(car.cnt);
+    }
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+
+        st = new StringTokenizer(br.readLine());
+        int x = Integer.parseInt(st.nextToken());
+        int y = Integer.parseInt(st.nextToken());
+        int d = Integer.parseInt(st.nextToken());
+        car = new Car(x, y, d);
+
+        board = new int[N][M];
+        visited = new boolean[N][M];
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < M; j++) {
+                board[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+
+        play();
+    }
+
+    static class Car{
+        int x, y, d, cnt;
+
+        Car(int x, int y, int d) {
+            this.x = x;
+            this.y = y;
+            this.d = d;
+            this.cnt = 1;
+        }
+
+        public void moveGo(int x, int y, int d) {
+            this.x = x;
+            this.y = y;
+            this.d = d;
+            this.cnt++;
+        }
+
+        public void moveBack(int x, int y, int d) {
+            this.x = x;
+            this.y = y;
+            this.d = d;
+        }
+    }
+}
+
+/*
+ * 세부조건 확인 잘하기
+ * - moveCar에서 바로 좌회전하면서 이동여부 확인 (현재 위치부터 아님)
+ */