4.岛屿数量 4.岛屿数量 题目 给你一个由'1'(陆地)和'0'(水)组成的二维网格,请你计算网格中的岛屿数量。 岛屿总是被水包围,并且每座岛屿只能由水平方向或竖直方向上相邻的陆地连接形成。 此外,你可以假设该网格的四条边均被水包围。 输入:grid = [ ["1","1","1","1","0"], ["1","1","0","1","0"], ["1","1","0","0","0"], ["0","0","0","0","0"] ] 输出:1 Echo Hou...大约 2 分钟DFS递归