거리두기

class Solution {
        class Point{
            Point(int r, int c, int d){
                row = r;
                col = c;
                dist = d;
            }
            int row, col, dist;
        }

        int [][] D = {{-1,0}, {1,0}, {0,-1}, {0,1}};
        boolean bfs(String[] place, int row, int col){
            boolean[][]visited = new boolean[5][5];
            Queue<Point> q = new LinkedList<>();
            visited[row][col] = true;
            q.add(new Point(row, col, 0));

            while(!q.isEmpty()){
                Point curr = q.remove();

                if(curr.dist > 2) continue;
                if(curr.dist != 0 && place[curr.row].charAt(curr.col) == 'P') return false;
                for(int i=0; i<4; i++){
                    int curr_row = curr.row + D[i][0], curr_col = curr.col + D[i][1];
                    if(curr_row <0 || curr_row>4 || curr_col < 0|| curr_col>4) continue;
                    if(visited[curr_row][curr_col]) continue;
                    if(place[curr_row].charAt(curr_col) == 'X') continue;
                    visited[curr_row][curr_col] = true;
                    q.add(new Point(curr_row, curr_col, curr.dist + 1));
                }
            }
            return true;
        }
        boolean check(String[] place){
            for(int r=0; r<5; r++){
                for(int c =0; c<5; c++){
                    if(place[r].charAt(c) == 'P'){
                        if(bfs(place,r ,c) ==false) return false;
                    }
                }
            }
            return true;
        }
        public int[] solution(String[][] places){
            int[] answer = new int[5];
            for(int i =0; i<5; ++i){
                if(check(places[i])) answer[i] = 1;
                else answer[i] = 0;
            }

            return answer;
        }
    }

• Point를 선언하여 row, col, dist를 받게한다

• 배열 D를 통해 상, 하, 좌, 우를 만든다
• bfs함수로

class Solution {
    static int[] dx = {-1, 0, 1, 0};
    static int[] dy = {0, 1, 0, -1};
    static boolean[][] visit;

    static int[] answer;

    public void dfs(int num, int x, int y, int count, String[] places){
        if (count > 2) return;
        if (count > 0 && count <= 2 && places[x].charAt(y) == 'P'){
            //2칸 범위내에 다른 응시자가 있을 경우 거리두기 미준수로 0처리
            answer[num] = 0;
            return;
        }
        for (int i = 0; i < 4; i++) {
            int nx = x + dx[i];
            int ny = y + dy[i];
            //배열 범위 밖으로 초과하는지 여부 검사, 파티션으로 분리되어 있는 경우 상관 없음.
            if (nx >= 0 && nx < 5 && ny >= 0 && ny < 5 && places[nx].charAt(ny) != 'X') {
                if (visit[nx][ny]) continue; //이미 방문한 곳일 경우 생략
                visit[nx][ny] = true;
                dfs(num, nx, ny, count + 1, places);
                visit[nx][ny] = false;
            }
        }
    }

    public int[] solution(String[][] places) {
        answer = new int[places.length];
        for (int i = 0; i < places.length; i++) {
            answer[i] = 1;
        }

        for (int i = 0; i < places.length; i++) {
            visit = new boolean[5][5];
            for (int j = 0; j < 5; j++) {
                for (int k = 0; k < 5; k++) {
                    if (places[i][j].charAt(k) == 'P'){
                        visit[j][k] = true;
                        dfs(i, j, k, 0, places[i]);
                        visit[j][k] = false;
                    }
                }
            }
        }
        return answer;
    }
}