[BOJ] 달이 차오른다, 가자.

[BOJ] 달이 차오른다, 가자.

Problem URL : 달이 차오른다, 가자.

#include<iostream>
#include<queue>
#include<string>
#define MAX 50

using namespace std;

int n, m;
char map[MAX][MAX];
bool visit[MAX][MAX][1 << 6]; // 6개의 key에 대한 비트마스크

pair<int, int> start;

int dx[] = { 0, 0, 1, -1 };
int dy[] = { 1, -1, 0, 0 };

// 움직일 때 미로 각각의 격자에서의 정보
struct Info {
    int x;
    int y;
    int cnt;
    int key;
    Info(int _x, int _y, int _cnt, int _key) : x(_x), y(_y), cnt(_cnt), key(_key) {};
};

bool hasKey(int key, char door) {
    int hasKey = key & (1 << (int(door) - 'A'));
    return hasKey != 0;
}

int bfs(int a, int b) {
    queue<Info> q;
    visit[a][b][0] = true;
    q.push(Info(a,b,0,0));

    while (q.empty() == 0) {
        int x = q.front().x;
        int y = q.front().y;
        int cnt = q.front().cnt;
        int key = q.front().key;
        q.pop();

        if (map[x][y] == '1') return cnt;

        for (int i = 0; i < 4; i++) {
            int nx = x + dx[i];
            int ny = y + dy[i];

            if (nx < 0 || ny < 0 || nx >= n || ny >= m || visit[nx][ny][key]) {
                continue;
            }
            if (map[nx][ny] == '.' || map[nx][ny] == '1') {
                visit[nx][ny][key] = true;
                q.push(Info(nx, ny, cnt + 1, key));
            } else if ('a' <= map[nx][ny] && map[nx][ny] <= 'f') {
                int tmpKey = key | (1 << (int(map[nx][ny] - 'a')));
                visit[nx][ny][tmpKey] = true;
                q.push(Info(nx, ny, cnt + 1, tmpKey));
            } else if ('A' <= map[nx][ny] && map[nx][ny] <= 'F') {
                if (hasKey(key, map[nx][ny])){
                    visit[nx][ny][key] = true;
                    q.push(Info(nx, ny, cnt + 1, key));
                }
            }
        }
    }
    return -1;
}


int main(void) {
    ios::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);

    cin >> n >> m;
    for (int i = 0; i < n; i++) {
        string input; 
        cin >> input;
        for (int j = 0; j < m; j++) {
            map[i][j] = input[j];
            if (map[i][j] == '0') {
                start.first = i;
                start.second = j;
                map[i][j] = '.';
            }
        }
    }

    cout << bfs(start.first, start.second) << endl;

    return 0;
}