Solution.cpp

class Solution {
public:
    const static inline vector<int> dirs = {-1, 0, 1, 0, -1};

    int getFood(vector<vector<char>>& grid) {
        int m = grid.size(), n = grid[0].size();
        queue<pair<int, int>> q;
        for (int i = 0, x = 1; i < m && x == 1; ++i) {
            for (int j = 0; j < n; ++j) {
                if (grid[i][j] == '*') {
                    q.emplace(i, j);
                    x = 0;
                    break;
                }
            }
        }
        int ans = 0;
        while (!q.empty()) {
            ++ans;
            for (int t = q.size(); t; --t) {
                auto [i, j] = q.front();
                q.pop();
                for (int k = 0; k < 4; ++k) {
                    int x = i + dirs[k], y = j + dirs[k + 1];
                    if (x >= 0 && x < m && y >= 0 && y < n) {
                        if (grid[x][y] == '#') return ans;
                        if (grid[x][y] == 'O') {
                            grid[x][y] = 'X';
                            q.emplace(x, y);
                        }
                    }
                }
            }
        }
        return -1;
    }
};