적록색약

https://www.acmicpc.net/problem/10026

소스코드

Main

   static int N;
    static char [][] arr;
    static boolean visits[][];
    static int dx[] = {-1,0,0,1};
    static int dy[] = {0,1,-1,0};

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        N =Integer.parseInt(br.readLine());
        StringBuilder sb = new StringBuilder();
        StringTokenizer st ;
        visits = new boolean[N+1][N+1];
        arr = new char[N+1][N+1];
        for (int i = 0; i <N ; i++) {
            st = new StringTokenizer(br.readLine());
            String Value = st.nextToken();
            for (int j = 0; j <N ; j++) {
               arr[i][j] = Value.charAt(j);
            }

        }
        //정상일때
        int Ncnt =0;
        for (int i = 0; i <N ; i++) {
            for (int j = 0; j <N ; j++) {
                if(!visits[i][j]){
                    dfs(i,j);
                    Ncnt++;
                }
            }
        }


        visits = new boolean[N+1][N+1];
        //적록색약일때
        int abCnt=0;
        for (int i = 0; i <N ; i++) {
            for (int j = 0; j <N ; j++) {
                if(arr[i][j]=='G'){
                    arr[i][j] = 'R';
                }
            }
        }

        for (int i = 0; i < N; i++) {
            for (int j = 0; j < N; j++) {
                if(!visits[i][j]){
                    dfs(i,j);
                    abCnt++;
                }
            }
        }


        sb.append(Ncnt).append(" ").append(abCnt);


        System.out.println(sb.toString());

    }

dfs

    public static void dfs(int x, int y){
        
        visits[x][y] = true;
        char colorChar = arr[x][y];

        for (int k = 0; k <4 ; k++) {
                int newX = x+dx[k];
                int newY = y+dy[k];

                if(newX < 0||newY < 0 || newX > N ||newY >N){
                    continue;
                }
                if(!visits[newX][newY] && arr[newX][newY]== colorChar){
                    dfs(newX,newY);
                }
        }
    }
    
    

생각할 것

1. dfs, bfs 중 어떤거 써서풀지
2. 상하좌우를 어떻게 방문하고, 방문했을때와 안했을때 구분을 어떻게 할지

참고

https://zzang9ha.tistory.com/227