지게차와 크레인

forklift_crane.java

@@ -0,0 +1,100 @@
+import java.util.*;
+
+class Solution {
+    char[][] grid;
+    boolean[][] visited;
+    int n, m;
+    int[] dx = {0, 0, 1, -1};
+    int[] dy = {1, -1, 0, 0};
+    public int solution(String[] storage, String[] requests) {
+        n = storage.length;
+        m = storage[0].length();
+        // 여백 포함 grid 초기화 (n+2, m+2), 테두리는 '0'
+        grid = new char[n + 2][m + 2];
+        for (char[] row : grid) Arrays.fill(row, '0');
+        for(int i=0;i<n;i++){
+            for(int j=0;j<m;j++){
+                grid[i+1][j+1]=storage[i].charAt(j);
+            }
+        }
+
+        for (String req : requests) {
+            if (req.length() == 1) {
+                forklift(req.charAt(0));
+            } else {
+                crane(req.charAt(0));
+            }
+        }
+
+        int answer = 0;
+        for (int i = 1; i <= n; i++)
+            for (int j = 1; j <= m; j++)
+                if (grid[i][j] != '0') answer++;
+
+        return answer;
+    }
+
+    public void bfs() {
+        visited = new boolean[n + 2][m + 2];
+        Queue<int[]>queue = new ArrayDeque<>();
+        queue.add(new int[]{0,0}); //외부취급 모서리
+        visited[0][0] = true;
+        while (!queue.isEmpty()) {
+            int[] cur = queue.poll();
+            int x = cur[0], y = cur[1];
+
+            for (int dir = 0; dir < 4; dir++) {
+                int nx = x + dx[dir];
+                int ny = y + dy[dir];
+
+                // 범위 체크, 이미 방문했는지 체크
+                if (nx < 0 || nx >= n+2 || ny < 0 || ny >= m+2)
+                    continue;
+                if (visited[nx][ny])
+                    continue;
+
+                // 빈 공간('0')만 타고 퍼져나감
+                if (grid[nx][ny] != '0')
+                    continue;
+
+                visited[nx][ny] = true;
+                queue.add(new int[]{nx, ny});
+            }
+        }
+    }
+
+    public void forklift(char type) {
+        bfs();// 먼저 외부 연결 상태 갱신
+         List<int[]> toRemove = new ArrayList<>();
+
+        for(int i=1;i<=n;i++){
+            for(int j=1;j<=m;j++){
+                if(grid[i][j]!=type)
+                    continue;
+                for (int dir = 0; dir < 4; dir++) {
+                    int nx = i + dx[dir];
+                    int ny = j + dy[dir];
+                    if (visited[nx][ny]) {
+                        toRemove.add(new int[]{i, j});
+                        break;
+                    }
+                }
+            }
+        }
+        // 모아둔 위치들 한꺼번에 제거
+        for (int[] pos : toRemove) {
+            grid[pos[0]][pos[1]] = '0';
+        }
+    }
+
+    public void crane(char type) {
+        //grid를 훑으면서 type인 칸을 전부 '0'으로 변경
+        for(int i=1;i<=n;i++){
+            for(int j=1;j<=m;j++){
+                if(grid[i][j]==type){
+                    grid[i][j]='0';
+                }
+            }
+        }
+    }
+}