题解 | #岛屿数量#

class Solution {
  public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 判断岛屿数量
     * @param grid char字符型vector<vector<>>
     * @return int整型
     */
    int vis[210][210] = {0};
    int dx[4] = {1, -1, 0, 0};
    int dy[4] = {0, 0, 1, -1};
    int n, m;
    int solve(vector<vector<char> >& grid) {
        n = grid.size();
        m = grid[0].size();

        int ret = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (grid[i][j] == '1' && !vis[i][j]) {
                    ret++;
                     count(grid, i, j);

                }
            }
        }


        return ret;
    }

    void count(vector<vector<char> >& grid, int i, int j) {
        vis[i][j] = 1;
        
        for (int k = 0; k < 4; k++) {
            int a = i + dx[k];
            int b = j + dy[k];
            if (a < n && a >= 0 && b < m && b >= 0 && grid[a][b] == '1' && !vis[a][b]) {
                
                count(grid, a, b);
            }
        }

        
    }


};