programmers_inquiry_kakao_friends_coloring_book_submission_code_rejected

solution.java

import java.util.*;

class Solution {
    private final int NON_COLORING_AREA = 0;
    private final int VISITED = -1;
    public int[] solution(int m, int n, int[][] picture) {
        int numberOfArea = 0;
        int maxSizeOfOneArea = 0;
        for (int row = 0; row < picture.length; row++) {
            for (int col = 0; col < picture[row].length; col++) {
                if (picture[row][col] == NON_COLORING_AREA) continue; 
                if (picture[row][col] == VISITED) continue;
                
                numberOfArea++;
                int sizeOfArea = visitArea(picture, row, col);
                if (maxSizeOfOneArea < sizeOfArea) maxSizeOfOneArea = sizeOfArea;
            }
        }

        int[] answer = new int[2];
        answer[0] = numberOfArea;
        answer[1] = maxSizeOfOneArea;
        return answer;
    }
    
    private int visitArea(int[][] map, int row, int col) {
        int areaCount = 0;
        int areaColor = map[row][col];
        int[] dRow = {0, 0, 1, -1};
        int[] dCol = {1, -1, 0, 0};
        
        Queue<Pos> queue = new LinkedList<>();
        Pos startPos = new Pos(row, col);
        queue.add(startPos);
        while (!queue.isEmpty()) {
            Pos pos = queue.poll();
            
            if (!isValidPos(map, pos)) continue;
            if (map[pos.row][pos.col] == NON_COLORING_AREA) continue;
            if (map[pos.row][pos.col] == VISITED) continue;
            if (map[pos.row][pos.col] != areaColor) continue;
            
            areaCount++;
            map[pos.row][pos.col] = VISITED;
            for (int dir = 0; dir < dRow.length; dir++) {
                int movedRow = pos.row + dRow[dir];
                int movedCol = pos.col + dCol[dir];
                Pos movedPos = new Pos(movedRow, movedCol);
                queue.add(movedPos);
            }
        }
        
        return areaCount;
    }
    
    private boolean isValidPos(int[][] map, Pos pos) {
        return 0 <= pos.row && pos.row < map.length &&
            0 <= pos.col && pos.col < map[pos.row].length;
    }
    
    private class Pos {
        int row;
        int col;
        
        Pos (int row, int col) {
            this.row = row;
            this.col = col;
        }
    }
}