unannn:: boj 3190_뱀_이윤환.java 추가

Author: unannn

common/boj/뱀/3190_뱀_이윤환.java

@@ -0,0 +1,104 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    private static final int[] dr = {0, -1, 0, 1};
+    private static final int[] dc = {1, 0, -1, 0};
+    
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        int N = Integer.parseInt(br.readLine());
+        int[][] board = new int[N][N];
+
+        int K = Integer.parseInt(br.readLine());
+        for (int i = 0; i < K; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int r = Integer.parseInt(st.nextToken()) - 1;
+            int c = Integer.parseInt(st.nextToken()) - 1;
+            board[r][c] = 1;
+        }
+
+        int L = Integer.parseInt(br.readLine());
+        int direction = 0; //오른쪽
+        Deque<int[]> snake = new ArrayDeque<>();
+        snake.addFirst(new int[]{0, 0});
+        board[0][0] = 2;
+
+        int answer = 0;
+        for(int i = 0; i < L; i++){
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int X = Integer.parseInt(st.nextToken());
+            char C = st.nextToken().charAt(0);
+
+            while(answer < X){
+                answer++;
+                int[] current = snake.getFirst();
+                int[] next = new int[2];
+                next[0] = current[0] + dr[direction];
+                next[1] = current[1] + dc[direction];
+
+                if(isWall(board, next[0], next[1]) || isBody(board, next[0], next[1])){
+                    System.out.println(answer);
+                    return;
+                }
+
+                //다음 머리의 좌표를 추가
+                snake.addFirst(next);
+                
+                if(!isApple(board,next[0], next[1])){
+                    int[] tail = snake.getLast();
+                    board[tail[0]][tail[1]] = 0;
+                    snake.removeLast();
+                }
+                
+                board[next[0]][next[1]] = 2;
+            }
+            direction = changeDirection(direction, C);
+        }
+
+        answer++;
+        int[] current = snake.getFirst();
+        int[] next = new int[2];
+        next[0] = current[0] + dr[direction];
+        next[1] = current[1] + dc[direction];
+
+        while(!isWall(board, next[0], next[1]) && !isBody(board, next[0], next[1])){
+            snake.addFirst(next);
+            if(isApple(board,next[0], next[1])){
+                board[next[0]][next[1]] = 2;
+            } else{
+                int[] tail = snake.getLast();
+                board[tail[0]][tail[1]] = 0;
+                snake.removeLast();
+            }
+            answer++;
+            current = snake.getFirst();
+            next = new int[2];
+            next[0] = current[0] + dr[direction];
+            next[1] = current[1] + dc[direction];
+        }
+
+        System.out.println(answer);
+    }
+
+    private static int changeDirection(int d, char C){
+        if(C == 'L'){
+         return (d + 1) % 4;
+        }else{
+            return (d - 1) < 0 ? 3 : d - 1;
+        }
+    }
+
+    private static boolean isApple(int[][] board, int r, int c){
+        return board[r][c] == 1;
+    }
+    private static boolean isWall(int[][] board, int r, int c){
+        return (r < 0 || r >= board.length) || (c < 0 || c >= board.length);
+    }
+
+    private static boolean isBody(int[][] board, int r, int c){
+        return board[r][c] == 2;
+    }
+}